Useful Sass Mixins and extend, usable in most projects.

extends.scss

// Clearfix
%clearfix {
  zoom: 1;
	&:before,
	&:after {
		display: table;
		content: "";
	}
	&:after {
		clear: both;
	}
}

mixin.scss

//Rem generator
$baseline-px: 16px;

@mixin rem($property, $px-values) {
  // Convert the baseline into rems
	$baseline-rem: $baseline-px / 1rem;
	// Print the first line in pixel values
	#{$property}: $px-values;
	// If there is only one (numeric) value, return the property/value line for it.
	@if type-of($px-values) == "number" {
		#{$property}: $px-values / $baseline-rem; }
	@else {
		// Create an empty list that we can dump values into
		$rem-values: unquote("");
		@each $value in $px-values {
			// If the value is zero, return 0
			@if $value == 0 {
				$rem-values: append($rem-values, $value); }
			@else {
				$rem-values: append($rem-values, $value / $baseline-rem); } }
		// Return the property and its list of converted values
		#{$property}: $rem-values; } }


//Disable selection
@mixin no-select {
	-webkit-user-select: none;
	-moz-user-select: none;
	-ms-user-select: none;
	user-select: none;
}

@mixin iconify( $code: null ){
	@if $code {
		content: "#{$code}";
	} @else {
		@content;
	}
	font-family: 'FontAwesome';
	font-weight: normal;
	font-style: normal;
	text-decoration: inherit;
	-webkit-font-smoothing: antialiased;
	*margin-right: .3em;
}