My custom SCSS prefixer mixins collection

_mixin.scss

@mixin size($width-param, $height-param:0) {
  width: $width-param;

  @if $height-param !=0 {
    height: $height-param;
  }

  @else {
    height: $width-param;
  }
}

@mixin flex-center() {
  @include display-flex-init();
  @include justify-content(center);
  @include align-items(center);
}

@mixin pad-x($value) {
  padding-left: $value;
        padding-right: $value;
}
@mixin margin-x($value) {
  margin-left: $value;
        margin-right: $value;
}

@mixin center-x-absolute() {
  left: 50%;
  @include transform(translateX(-50%));
}

@mixin center-y-absolute() {
  top: 50%;
  @include transform(translateY(-50%));
}

@mixin flex-start() {
  @include display-flex();
  @include justify-content(flex-start);
  @include align-items(flex-start);
}

@mixin flex-end() {
  @include display-flex();
  @include justify-content(flex-end);
  @include align-items(flex-end);
}


@mixin display-flex($flex:0, $display:true, $justify-content:0, $align-items:0, $align-content:0, $placement:0, $direction:0, $wrap:0) {
  @if $flex !=0 {
    @include flex($flex);
  }

  @if $display==true {
    @include display-flex-init();
  }

  @if $justify-content !=0 {
    @include justify-content($justify-content);
  }
  
  @if $align-items !=0 {
    @include align-items($align-items);
  }

  @if $align-content !=0 {
    @include align-content($align-content);
  }

  @if $placement==start {
    @include justify-content(flex-start);
    @include align-items(flex-start);
  }

  @else if $placement==end {
    @include justify-content(flex-end);
    @include align-items(flex-end);
  }

  @else if $placement==center {
    @include justify-content(center);
    @include align-items(center);
  }

  @if $direction !=0 {
    @include flex-direction($direction);
  }

  @if $wrap !=0 {
    @include flex-wrap($wrap);
  }
}

@mixin pos-abs($top:false, $right:false, $bottom:false, $h:false, $v:false, $all:false, $left:false, $abs:true) {
  @if $abs==true {
    position: absolute;
  }

  @if $top !=false {
    top: $top;
  }

  @if $right !=false {
    right: $right;
  }

  @if $bottom !=false {
    bottom: $bottom;
  }

  @if $left !=false {
    left: $left;
  }

  @if $h !=false {
    left: $h;
    right: $h;
  }

  @if $v !=false {
    top: $v;
    bottom: $v;
  }

  @if $all !=false {
    top: $all;
    right: $all;
    bottom: $all;
    left: $all;
  }
}

@mixin space-reset() {
  margin: 0;
  padding: 0;
}

@mixin media-break ($break-point, $device-type: max, $break-type: width, $media-type: screen) {
  $break-logic: $device-type+'-'+$break-type;

  @media #{$media-type} and (#{$break-logic}: $break-point) {
    @content;
  }
}

_prefix.scss

/// Mixin to prefix several properties at once
/// @author Kitty Giraudel
/// @param {Map} $declarations - Declarations to prefix
/// @param {List} $prefixes (()) - List of prefixes to print
@mixin prefix($declarations, $prefixes: (), $important: 0) {

  @each $property,
  $value in $declarations {
    @each $prefix in $prefixes {
      @if $important==1 {
        #{'-' + $prefix + '-' + $property}: #{$value + '!important'};
      }

      @else {
        #{'-' + $prefix + '-' + $property}: $value;
      }
    }

    // Output standard non-prefixed declaration
    @if $important==1 {
      #{$property}: #{$value + '!important'};
    }

    @else {
      #{$property}: $value;
    }
  }
}

@mixin prefix-value($declarations, $prefixes: (), $important: 0) {

  @each $property,
  $value in $declarations {
    @each $prefix in $prefixes {
      @if $important==1 {
        #{$property}: #{'-' + $prefix + '-' + $value + '!important'};
      }

      @else {
        #{$property}: #{'-' + $prefix + '-' + $value};
      }
    }

    // Output standard non-prefixed declaration
    @if $important==1 {
      #{$property}: #{$value + '!important'};
    }

    @else {
      #{$property}: $value;
    }
  }
}


/// Mixins
/// @author Andy Crone | @andycrone_
/// + Popular mixins including vendor prefixes for cross-browser support

/*
align-content
align-items
align-self
animation
animation-delay
appearance
backdrop-filter
background-size
border-radius
box-shadow
box-sizing
calc
display-flex
filter
flex
flex-direction
flex-wrap
justify-content
keyframes
linear-gradient
object-fit
transform
transform-origin
transition
user-select
word-break
*/

@mixin align-content($value, $important: 0) {
  -ms-flex-line-pack: center;
  @include prefix((align-content: $value), webkit, $important);
}

@mixin align-items($value, $important: 0) {
  -ms-flex-align: $value;
  -webkit-box-align: $value;
  -moz-box-align: $value;
  @include prefix((align-items: $value), webkit, $important);
}

@mixin align-self($value, $important: 0) {
  -ms-flex-item-align: $value;
  -ms-grid-row-align: $value;
  @include prefix((align-self: $value), webkit, $important);
}

@mixin animation($value, $important: 0) {
  @include prefix((animation: $value), webkit moz ms o, $important);
}

@mixin animation-delay($value, $important: 0) {
  @include prefix((animation-delay: $value), webkit moz o, $important);
}

@mixin appearance($value, $important: 0) {
  @include prefix((appearance: $value), webkit mozv, $important);
}

@mixin backdrop-filter($value, $important: 0) {
  @include prefix((backdrop-filter: $value), webkit, $important);
}

@mixin background-size($value, $important: 0) {
  @include prefix((background-size: $value), webkit moz o, $important);
}

@mixin border-radius($value, $important: 0) {
  @include prefix((border-radius: $value), webkit moz, $important);
}

@mixin box-shadow($value, $important: 0) {
  @include prefix((box-shadow: $value), webkit moz, $important);
}

@mixin box-sizing($value, $important: 0) {
  @include prefix((box-sizing: $value), webkit moz, $important);
}

@mixin calc($tag, $value, $important: 0) {
  @include prefix-value(($tag: $value), webkit ms, $important);
}

@mixin display-flex-init($important: 0) {
  display: -webkit-box;
  display: -moz-box;
  display: -ms-flexbox;
  @include prefix-value((display: flex), webkit, $important);
}

@mixin filter($value, $important: 0) {
  @include prefix((filter: $value), webkit moz ms o, $important);
}

@mixin flex($value, $important: 0) {
  -webkit-box-flex: $value;
  -moz-box-flex: $value;
  @include prefix((flex: $value), webkit ms, $important);
}

@mixin flex-direction($value, $important: 0) {
  -webkit-box-orient: vertical;
  -webkit-box-direction: normal;
  -moz-box-orient: vertical;
  -moz-box-direction: normal;
  @include prefix((flex-direction: $value), webkit ms, $important);
}

@mixin flex-wrap($value: wrap, $important: 0) {
  @include prefix((flex-wrap: $value), webkit ms, $important);
}

@mixin justify-content($value, $important: 0) {
  -webkit-box-pack: $value;
  -moz-box-pack: $value;
  -ms-flex-pack: $value;
  @include prefix((justify-content: $value), webkit, $important);
}

@mixin keyframes($value) {
  @-webkit-keyframes #{$value} {
    @content;
  }

  @-moz-keyframes #{$value} {
    @content;
  }

  @-o-keyframes #{$value} {
    @content;
  }

  @keyframes #{$value} {
    @content;
  }
}

@mixin linear-gradient($angle, $gradient1, $gradient2) {
  background-color: $gradient2;
  /* Fallback Color */
  background-image: -webkit-gradient(linear, $angle, from($gradient1), to($gradient2));
  /* Saf4+, Chrome */
  /* Chrome 10+, Saf5.1+, iOS 5+ */
  /* FF3.6 */
  /* IE10 */
  /* Opera 11.10+ */
  @include prefix-value((background-image: linear-gradient($angle, $gradient1, $gradient2)), webkit moz ms o);
  filter: progid:DXImageTransform.Microsoft.gradient(GradientType=$angle, StartColorStr='#{$gradient1}', EndColorStr='#{$gradient2}');
}

@mixin object-fit($value, $important: 0) {
  @include prefix((object-fit: $value), o, $important);
}

@mixin transform($value, $important: 0) {
  @include prefix((transform: $value), webkit moz ms o, $important);
}

@mixin transform-origin($value, $important: 0) {
  @include prefix((transform-origin: $value), webkit moz ms o, $important);
}

@mixin transition($value, $important: 0) {
  -webkit-transition: #{'-webkit-'+ $value};
  transition: #{'-webkit-'+ $value};
  transition: #{$value + ', '+ '-webkit-'+ $value};
  @include prefix((transition: $value), webkit moz o, $important);
}

@mixin user-select($value, $important: 0) {
  -webkit-touch-callout: $value;
  @include prefix((user-select: $value), webkit khtml moz ms, $important);
}

@mixin word-break($value, $important: 0) {
  @include prefix((word-break: $value), ms, $important);
}