CSSのみで作るアイコンのサンプル集です。

                                
.chevron-right {
    box-sizing: border-box;
    position: relative;
    display: block;
    transform: scale(1.5);
    width: 22px;
    height: 22px;
    border: 2px solid transparent;
    border-radius: 100px;
}
.chevron-right::after {
    content: "";
    display: block;
    box-sizing: border-box;
    position: absolute;
    width: 10px;
    height: 10px;
    border-bottom: 2px solid;
    border-right: 2px solid;
    transform: rotate(-45deg);
    right: 6px;
    top: 4px;
}
                                
                              

                                
.chevron-left {
    box-sizing: border-box;
    position: relative;
    display: block;
    transform: scale(1.5);
    width: 22px;
    height: 22px;
    border: 2px solid transparent;
    border-radius: 100px;
}

.chevron-left::after {
    content: "";
    display: block;
    box-sizing: border-box;
    position: absolute;
    width: 10px;
    height: 10px;
    border-bottom: 2px solid;
    border-left: 2px solid;
    transform: rotate(45deg);
    left: 6px;
    top: 4px;
} 
                                
                              

                                
.chevron-up {
    box-sizing: border-box;
    position: relative;
    display: block;
    transform: scale(1.5);
    width: 22px;
    height: 22px;
    border: 2px solid transparent;
    border-radius: 100px;
}

.chevron-up::after {
    content: "";
    display: block;
    box-sizing: border-box;
    position: absolute;
    width: 10px;
    height: 10px;
    border-top: 2px solid;
    border-right: 2px solid;
    transform: rotate(-45deg);
    left: 4px;
    bottom: 2px;
} 
                                
                              

                                
.chevron-down {
    box-sizing: border-box;
    position: relative;
    display: block;
    transform: scale(1.5);
    width: 22px;
    height: 22px;
    border: 2px solid transparent;
    border-radius: 100px;
}

.chevron-down::after {
    content: "";
    display: block;
    box-sizing: border-box;
    position: absolute;
    width: 10px;
    height: 10px;
    border-bottom: 2px solid;
    border-right: 2px solid;
    transform: rotate(45deg);
    left: 4px;
    top: 2px;
} 
                                
                              

                                
.plus,
.plus::after {
    display: block;
    box-sizing: border-box;
    background: currentColor;
    border-radius: 10px;
}

.plus {
    margin-top: -2px;
    position: relative;
    transform: scale(1.5);
    width: 16px;
    height: 2px;
}

.plus::after {
    content: "";
    position: absolute;
    width: 2px;
    height: 16px;
    top: -7px;
    left: 7px;
} 
                                
                              

                                
.minus {
    box-sizing: border-box;
    position: relative;
    display: block;
    transform: scale(1.5);
    width: 16px;
    height: 2px;
    background: currentColor;
    border-radius: 10px;
} 
                                
                              

                                
.Check-maru {
    box-sizing: border-box;
    position: relative;
    display: block;
    transform: scale(1.5);
    width: 22px;
    height: 22px;
    border: 2px solid;
    border-radius: 100px;
}

.Check-maru::after {
    content: "";
    display: block;
    box-sizing: border-box;
    position: absolute;
    left: 3px;
    top: -1px;
    width: 6px;
    height: 10px;
    border-color: currentColor;
    border-width: 0 2px 2px 0;
    border-style: solid;
    transform-origin: bottom left;
    transform: rotate(45deg);
} 
                                
                              

                                
.Check-square {
    box-sizing: border-box;
    position: relative;
    display: block;
    width: 22px;
    height: 22px;
    border: 2px solid;
    transform: scale(1.5);
    border-radius: 4px;
}

.Check-square::after {
    content: "";
    display: block;
    box-sizing: border-box;
    position: absolute;
    left: 3px;
    top: -1px;
    width: 6px;
    height: 10px;
    border-width: 0 2px 2px 0;
    border-style: solid;
    transform-origin: bottom left;
    transform: rotate(45deg);
} 
                                
                              

                                
.Check-normal {
    box-sizing: border-box;
    position: relative;
    display: block;
    transform: scale(1.5);
    width: 22px;
    height: 22px;
    border: 2px solid transparent;
    border-radius: 100px;
}

.Check-normal::after {
    content: "";
    display: block;
    box-sizing: border-box;
    position: absolute;
    left: 3px;
    top: -1px;
    width: 6px;
    height: 10px;
    border-width: 0 2px 2px 0;
    border-style: solid;
    transform-origin: bottom left;
    transform: rotate(45deg);
} 
                                
                              

                                
.Chevron-Right-maru {
    box-sizing: border-box;
    position: relative;
    display: block;
    transform: scale(1.5);
    width: 22px;
    height: 22px;
    border: 2px solid;
    border-radius: 100px;
}

.Chevron-Right-maru::after {
    content: "";
    display: block;
    box-sizing: border-box;
    position: absolute;
    width: 6px;
    height: 6px;
    border-bottom: 2px solid;
    border-right: 2px solid;
    transform: rotate(-45deg);
    left: 5px;
    top: 6px;
} 
                                
                              

                                
.close {
    box-sizing: border-box;
    position: relative;
    display: block;
    transform: scale(1.5);
    width: 22px;
    height: 22px;
    border: 2px solid transparent;
    border-radius: 40px;
}

.close::after,
.close::before {
    content: "";
    display: block;
    box-sizing: border-box;
    position: absolute;
    width: 16px;
    height: 2px;
    background: currentColor;
    transform: rotate(45deg);
    border-radius: 5px;
    top: 8px;
    left: 1px;
}

.close::after {
    transform: rotate(-45deg)
} 
                                
                              

                                
.close-maru {
    box-sizing: border-box;
    position: relative;
    display: block;
    transform: scale(1.5);
    width: 22px;
    height: 22px;
    border: 2px solid;
    border-radius: 40px;
}

.close-maru::after,
.close-maru::before {
    content: "";
    display: block;
    box-sizing: border-box;
    position: absolute;
    width: 12px;
    height: 2px;
    background: currentColor;
    transform: rotate(45deg);
    border-radius: 5px;
    top: 8px;
    left: 3px;
}

.close-maru::after {
    transform: rotate(-45deg);
} 
                                
                              

                                
.hum-menu {
    transform: scale(1.5);
}

.hum-menu,
.hum-menu::after,
.hum-menu::before {
    box-sizing: border-box;
    position: relative;
    display: block;
    width: 20px;
    height: 2px;
    border-radius: 3px;
    background: currentColor;
}

.hum-menu::after,
.hum-menu::before {
    content: "";
    position: absolute;
    top: -6px;
}

.hum-menu::after {
    top: 6px;
} 
                                
                              

                                
.hum-menu-box {
    box-sizing: border-box;
    position: relative;
    display: block;
    transform: scale(1.5);
    width: 18px;
    height: 18px;
    border-radius: 3px;
    border: 2px solid;
}

.hum-menu-box::before {
    content: "";
    display: block;
    box-sizing: border-box;
    position: absolute;
    width: 10px;
    height: 2px;
    background: currentColor;
    border-radius: 3px;
    top:2px;
    left: 2px;
    box-shadow: 0 4px 0, 0 8px 0;
}

                                
                              

                                
.hum-menu-left {
    box-sizing: border-box;
    position: relative;
    display: block;
    width: 16px;
    height: 14px;
    transform: scale(1.5);
}

.hum-menu-left::after,
.hum-menu-left::before {
    content: "";
    position: absolute;
    box-sizing: border-box;
    display: block;
    height: 2px;
    border-radius: 4px;
    background: currentColor;
}

.hum-menu-left::before {
    width: 16px;
    box-shadow: 0 12px 0;
}

.hum-menu-left::after {
    width: 10px;
    top: 6px;
} 

                                
                              

                                
.hum-menu-left2 {
    transform: scale(1.5);
}

.hum-menu-left2,
.hum-menu-left2::after,
.hum-menu-left2::before {
    box-sizing: border-box;
    position: relative;
    display: block;
    width: 20px;
    height: 2px;
    border-radius: 3px;
    background: currentColor;
}

.hum-menu-left2::after,
.hum-menu-left2::before {
    content: "";
    position: absolute;
    top: -6px;
    width: 10px;
}

.hum-menu-left2::after {
    top: 6px;
    width: 14px;
} 

                                
                              

                                
.hum-menu-right {
    box-sizing: border-box;
    position: relative;
    display: block;
    width: 16px;
    height: 14px;
    transform: scale(1.5);
}

.hum-menu-right::after,
.hum-menu-right::before {
    content: "";
    position: absolute;
    box-sizing: border-box;
    display: block;
    height: 2px;
    border-radius: 4px;
    background: currentColor;
}

.hum-menu-right::before {
    width: 16px;
    box-shadow: 0 12px 0;
}

.hum-menu-right::after {
    width: 10px;
    right: 0;
    top: 6px;
} 

                                
                              

                                
.hum-menu-right2 {
    transform: scale(1.5);
}

.hum-menu-right2,
.hum-menu-right2::after,
.hum-menu-right2::before {
    box-sizing: border-box;
    position: relative;
    display: block;
    width: 20px;
    height: 2px;
    border-radius: 3px;
    background: currentColor;
}

.hum-menu-right2::after,
.hum-menu-right2::before {
    content: "";
    position: absolute;
    top: -6px;
    right: 0;
    width: 10px;
}

.hum-menu-right2::after {
    top: 6px;
    width: 14px;
} 

                                
                              

                                
.menu-grid {
    box-sizing: border-box;
    position: relative;
    display: block;
    transform: scale(1.5);
    width: 16px;
    height: 16px;
}

.menu-grid::before {
    content: "";
    display: block;
    box-sizing: border-box;
    position: absolute;
    width: 4px;
    height: 4px;
    background: currentColor;
    box-shadow:
    0 6px 0,
    6px 6px 0,
    12px 6px 0,
    6px 12px 0,
    12px 12px 0,
    6px 0 0,
    12px 0 0,
    0 12px 0;
} 
                                
                              

                                
.layout-grid {
    transform: scale(1.5);
}

.layout-grid,
.layout-grid::after,
.layout-grid::before {
    box-sizing: border-box;
    position: relative;
    display: block;
    width: 10px;
    height: 10px;
}

.layout-grid::after,
.layout-grid::before {
    content: "";
    position: absolute;
    height: 4px;
    border-left: 4px solid;
    border-right: 4px solid;
}

.layout-grid::before {
    top: 0;
}

.layout-grid::after {
    bottom: 0;
} 
                                
                              

                                
.arrow-right {
    box-sizing: border-box;
    position: relative;
    display: block;
    transform: scale(1.5);
    width: 22px;
    height: 22px;
}

.arrow-right::after,
.arrow-right::before {
    content: "";
    display: block;
    box-sizing: border-box;
    position: absolute;
    right: 3px;
}

.arrow-right::after {
    width: 8px;
    height: 8px;
    border-top: 2px solid;
    border-right: 2px solid;
    transform: rotate(45deg);
    bottom: 7px;
}

.arrow-right::before {
    width: 16px;
    height: 2px;
    bottom: 10px;
    background: currentColor;
} 

                                
                              

                                
.arrow-left {
    box-sizing: border-box;
    position: relative;
    display: block;
    transform: scale(1.5);
    width: 22px;
    height: 22px;
}

.arrow-left::after,
.arrow-left::before {
    content: "";
    display: block;
    box-sizing: border-box;
    position: absolute;
    left: 3px;
}

.arrow-left::after {
    width: 8px;
    height: 8px;
    border-bottom: 2px solid;
    border-left: 2px solid;
    transform: rotate(45deg);
    bottom: 7px;
}

.arrow-left::before {
    width: 16px;
    height: 2px;
    bottom: 10px;
    background: currentColor;
} 

                                
                              

                                
.arrow-right-maru {
    box-sizing: border-box;
    position: relative;
    display: block;
    width: 22px;
    height: 22px;
    border: 2px solid;
    transform: scale(1.5);
    border-radius: 20px;
}

.arrow-right-maru::after,
.arrow-right-maru::before {
    content: "";
    display: block;
    box-sizing: border-box;
    position: absolute;
    right: 4px;
}

.arrow-right-maru::after {
    width: 6px;
    height: 6px;
    border-top: 2px solid;
    border-right: 2px solid;
    transform: rotate(45deg);
    bottom: 6px;
}

.arrow-right-maru::before {
    width: 10px;
    height: 2px;
    bottom: 8px;
    background: currentColor;
} 

                                
                              

                                
.arrow-left-maru {
    box-sizing: border-box;
    position: relative;
    display: block;
    width: 22px;
    height: 22px;
    border: 2px solid;
    transform: scale(1.5);
    border-radius: 22px;
}

.arrow-left-maru::after,
.arrow-left-maru::before {
    content: "";
    display: block;
    box-sizing: border-box;
    position: absolute;
    left: 4px;
}

.arrow-left-maru::after {
    width: 6px;
    height: 6px;
    border-bottom: 2px solid;
    border-left: 2px solid;
    transform: rotate(45deg);
    bottom: 6px;
}

.arrow-left-maru::before {
    width: 10px;
    height: 2px;
    bottom: 8px;
    background: currentColor;
} 

                                
                              

                                
.enter {
    box-sizing: border-box;
    position: relative;
    display: block;
    transform: scale(1.5);
    width: 16px;
    height: 18px;
    border: 2px solid;
    border-left: 0;
    box-shadow:
    -8px -6px 0 -6px,
    -8px 6px 0 -6px;
}

.enter::after,
.enter::before {
    content: "";
    display: block;
    box-sizing: border-box;
    position: absolute;
    right: 4px;
}

.enter::before {
    background: currentColor;
    width: 16px;
    height: 2px;
    top: 6px;
}

.enter::after {
    width: 6px;
    height: 6px;
    border-right: 2px solid;
    border-top: 2px solid;
    top: 4px;
    transform: rotate(45deg);
} 

                                
                              

                                
.external {
    box-sizing: border-box;
    position: relative;
    display: block;
    transform: scale(1.5);
    width: 12px;
    height: 12px;
    box-shadow:
    -2px 2px 0 0,
    -4px -4px 0 -2px,
    4px 4px 0 -2px;
    margin-left: -2px;
    margin-top: 1px;
}

.external::after,
.external::before {
    content: "";
    display: block;
    box-sizing: border-box;
    position: absolute;
    right: -4px;
}

.external::before {
    background: currentColor;
    transform: rotate(-45deg);
    width: 12px;
    height: 2px;
    top: 1px;
}

.external::after {
    width: 8px;
    height: 8px;
    border-right: 2px solid;
    border-top: 2px solid;
    top: -4px;
} 

                                
                              

                                
.heart,
.heart::after {
border: 2px solid;
border-top-left-radius: 100px;
border-top-right-radius: 100px;
width: 10px;
height: 8px;
border-bottom: 0;
}

.heart {
    box-sizing: border-box;
    position: relative;
    transform:
        translate(
            calc(-10px / 2 * 1.5),
            calc(-6px / 2 * 1.5)
            )
            rotate(-45deg)
            scale(1.5);
    display: block;
}

.heart::after,
.heart::before {
    content: "";
    display: block;
    box-sizing: border-box;
    position: absolute;
}

.heart::after {
    right: -9px;
    transform: rotate(90deg);
    top: 5px;
}

.heart::before {
    width: 11px;
    height: 11px;
    border-left: 2px solid;
    border-bottom: 2px solid;
    left: -2px;
    top: 3px;
} 

                                
                              

                                
.home {
    box-sizing: border-box;
    position: relative;
    display: block;
    transform: scale(1.5);
    width: 18px;
    height: 14px;
    border: 2px solid;
    border-top: 0;
    border-radius: 2px;
    border-bottom-left-radius: 3px;
    border-bottom-right-radius: 3px;
    margin-bottom: -2px;
}

.home::after,
.home::before {
    content: "";
    display: block;
    box-sizing: border-box;
    position: absolute;
}

.home::before {
    border-top: 2px solid;
    border-left: 2px solid;
    border-top-left-radius: 4px;
    transform: rotate(45deg);
    top: -5px;
    border-radius: 3px;
    width: 14px;
    height: 14px;
    left: 0;
}

.home::after {
    width: 6px;
    height: 10px;
    background: currentColor;
    border-top-left-radius: 100px;
    border-top-right-radius: 100px;
    left: 4px;
    bottom: -2px;
} 

                                
                              

                                
.home2 {
    background:
        linear-gradient(to left,
        currentColor 5px,transparent 0)
        no-repeat 0 bottom/4px 2px,
        linear-gradient(to left,
        currentColor 5px,transparent 0)
        no-repeat right bottom/4px 2px;
    box-sizing: border-box;
    position: relative;
    display: block;
    transform: scale(1.5);
    width: 18px;
    height: 14px;
    border: 2px solid;
    border-top: 0;
    border-bottom: 0;
    border-top-right-radius: 3px;
    border-top-left-radius: 3px;
    border-bottom-right-radius: 0;
    border-bottom-left-radius: 0;
    margin-bottom: -2px;
}

.home2::after,
.home2::before {
    content: "";
    display: block;
    box-sizing: border-box;
    position: absolute;
}

.home2::before {
    border-top: 2px solid;
    border-left: 2px solid;
    border-top-left-radius: 4px;
    transform: rotate(45deg);
    top: -5px;
    border-radius: 3px;
    width: 14px;
    height: 14px;
    left: 0;
}

.home2::after {
    width: 8px;
    height: 10px;
    border: 2px solid;
    border-radius: 100px;
    border-bottom-left-radius: 0;
    border-bottom-right-radius: 0;
    border-bottom: 0;
    left: 3px;
    bottom: 0;
} 

                                
                              

                                
.import1 {
    box-sizing: border-box;
    position: relative;
    display: block;
    transform: scale(1.5);
    width: 18px;
    height: 14px;
    border: 2px solid;
    border-top: 0;
    box-shadow:
    -6px -8px 0 -6px,
    6px -8px 0 -6px;
}

.import1::after,
.import1::before {
    content: "";
    display: block;
    box-sizing: border-box;
    position: absolute;
}

.import1::before {
    background: currentColor;
    width: 2px;
    height: 14px;
    right: 6px;
    bottom: 5px;
}

.import1::after {
    width: 6px;
    height: 6px;
    border-right: 2px solid;
    border-bottom: 2px solid;
    right: 4px;
    bottom: 4px;
    transform: rotate(45deg);
} 

                                
                              

                                
.laptop {
    box-sizing: border-box;
    position: relative;
    display: block;
    transform: scale(1.5);
    width: 18px;
    height: 12px;
    border: 2px solid;
    border-radius: 2px;
}

.laptop::after {
    content: "";
    display: block;
    box-sizing: border-box;
    position: absolute;
    width: 22px;
    height: 2px;
    background: currentColor;
    left: -4px;
    bottom: -5px;
    border-radius: 100px;
} 

                                
                              

                                
.smartphone {
    background:
    linear-gradient(to left,
    currentColor 5px,transparent 0)
    no-repeat 4px 12px/2px 2px;
    box-sizing: border-box;
    position: relative;
    display: block;
    transform: scale(1.5);
    width: 14px;
    height: 20px;
    border: 2px solid;
    border-radius: 2px;
} 

                                
                              

                                
.list-icon {
    transform: scale(1.5);
}

.list-icon,
.list-icon::after,
.list-icon::before {
    box-sizing: border-box;
    position: relative;
    display: block;
    width: 10px;
    height: 2px;
    border-left: 6px double;
    border-right: 4px solid;
}

.list-icon::after,
.list-icon::before {
    content: "";
    position: absolute;
    left: -6px;
}

.list-icon::after {
    bottom: 4px;
}

.list-icon::before {
    top: 4px;
} 

                                
                              

                                
.link-icon {
    box-sizing: border-box;
    position: relative;
    display: block;
    transform: rotate(-45deg) scale(1.5);
    width: 8px;
    height: 2px;
    background: currentColor;
    border-radius: 4px;
}

.link-icon::after,
.link-icon::before {
    content: "";
    display: block;
    box-sizing: border-box;
    position: absolute;
    border-radius: 3px;
    width: 8px;
    height: 10px;
    border: 2px solid;
    top: -4px;
}

.link-icon::before {
    border-right: 0;
    border-top-left-radius: 40px;
    border-bottom-left-radius: 40px;
    left: -6px;
}

.link-icon::after {
    border-left: 0;
    border-top-right-radius: 40px;
    border-bottom-right-radius: 40px;
    right: -6px;
} 

                                
                              

                                
.mail-icon,
.mail-icon::after {
    display: block;
    box-sizing: border-box;
    height: 14px;
    border: 2px solid;
}

.mail-icon {
    overflow: hidden;
    transform: scale(1.5);
    position: relative;
    width: 18px;
    border-radius: 2px;
}

.mail-icon::after {
    content: "";
    position: absolute;
    border-radius: 3px;
    width: 14px;
    transform: rotate(-45deg);
    bottom: 3px;
    left: 0;
} 

                                
                              

                                
.more-icon {
    transform: scale(1.5);
}

.more-icon,
.more-icon::after,
.more-icon::before {
    box-sizing: border-box;
    position: relative;
    display: block;
    width: 4px;
    height: 4px;
    background: currentColor;
    border-radius: 100%;
}

.more-icon::after,
.more-icon::before {
    content: "";
    position: absolute;
    top: 0;
}

.more-icon::after {
    left: -6px;
}

.more-icon::before {
    right: -6px;
} 

                                
                              

                                
.search-icon {
    box-sizing: border-box;
    position: relative;
    display: block;
    transform: scale(1.5);
    width: 16px;
    height: 16px;
    border: 2px solid;
    border-radius: 100%;
    margin-left: -4px;
    margin-top: -4px;
}

.search-icon::after {
    content: "";
    display: block;
    box-sizing: border-box;
    position: absolute;
    border-radius: 3px;
    width: 2px;
    height: 8px;
    background: currentColor;
    transform: rotate(-45deg);
    top: 10px;
    left: 12px;
} 

                                
                              

                                
.toggle-Off-icon,
.toggle-Off-icon::before {
    display: block;
    box-sizing: border-box;
    border-radius: 20px;
}

.toggle-Off-icon {
    border: 2px solid;
    position: relative;
    transform: scale(1.5);
    width: 24px;
    height: 14px;
}

.toggle-Off-icon::before {
    content: "";
    position: absolute;
    width: 6px;
    height: 6px;
    background: currentColor;
    top: 2px;
    left: 12px;
} 

                                
                              

                                
.toggle-On-icon,
.toggle-On-icon::before {
    display: block;
    box-sizing: border-box;
    border-radius: 20px;
}

.toggle-On-icon {
    border: 2px solid;
    position: relative;
    transform: scale(1.5);
    width: 24px;
    height: 14px;
}

.toggle-On-icon::before {
    content: "";
    position: absolute;
    width: 6px;
    height: 6px;
    background: currentColor;
    top: 2px;
    left: 2px;
} 

                                
                              

                                
.user-add-icon {
    display: block;
    transform: scale(1.5);
    box-sizing: border-box;
    width: 20px;
    height: 18px;
    background:
    linear-gradient(
    to left,
    currentColor 8px,
    transparent 0)
    no-repeat 14px 6px/6px 2px,
    linear-gradient(
    to left,
    currentColor 8px,
    transparent 0)
    no-repeat 16px 4px/2px 6px;
}

.user-add-icon::after,.user-add-icon::before {
    content: "";
    display: block;
    box-sizing: border-box;
    position: absolute;
    border: 2px solid;
}

.user-add-icon::before {
    width: 8px;
    height: 8px;
    border-radius: 30px;
    top: 0;
    left: 2px;
}

.user-add-icon::after {
    width: 12px;
    height: 9px;
    border-bottom: 0;
    border-top-left-radius: 3px;
    border-top-right-radius: 3px;
    top: 9px;
} 

                                
                              

                                
.user-icon {
    display: block;
    transform: scale(1.5);
    box-sizing: border-box;
    width: 12px;
    height: 18px;
}

.user-icon::after,
.user-icon::before {
    content: "";
    display: block;
    box-sizing: border-box;
    position: absolute;
    border: 2px solid;
}

.user-icon::before {
    width: 8px;
    height: 8px;
    border-radius: 30px;
    top: 0;
    left: 2px;
}

.user-icon::after {
    width: 12px;
    height: 9px;
    border-bottom: 0;
    border-top-left-radius: 3px;
    border-top-right-radius: 3px;
    top: 9px;
} 

                                
                              

                                
.info-icon {
    box-sizing: border-box;
    position: relative;
    display: block;
    transform: scale(1.5);
    width: 20px;
    height: 20px;
    border: 2px solid;
    border-radius: 40px;
}

.info-icon::after,
.info-icon::before {
    content: "";
    display: block;
    box-sizing: border-box;
    position: absolute;
    border-radius: 3px;
    width: 2px;
    background: currentColor;
    left: 7px;
}

.info-icon::after {
    bottom: 2px;
    height: 8px;
}

.info-icon::before {
    height: 2px;
    top: 2px;
}