Compiles whole font-family @font-face rules. Uses a mixin and (preferably) separate file for each font-family and compiles css with @font-face rules for each weight/style. example.scss shows a font-family file, the other is the actual mixin.

example.scss

// example font-face file

/* -----------------------------------------
  Geometrica Font
------------------------------------------*/

// Source:
// -------
// DesignCuts: Exceptional Best-Selling Fonts Complete
// Latinotype

// variables
$path-prefix: './webfonts';
$font-subfolder: 'geometrica';
$font-name: 'Geometrica';
$font-family: 'geometrica';
$font-formats: EOT WOFF SVG TTF;

@import 'mixin-fontface';

/* Thin */
@include fontFace( #{$font-name}-Thin, 100, normal );
/* Thin Italic */
@include fontFace( #{$font-name}-ThinIt, 100, italic );
/* Extra Light */
@include fontFace( #{$font-name}-ExtraLight, 200, normal );
/* Extra Light Italic */
@include fontFace( #{$font-name}-ExtraLightIt, 200, italic );
/* Light */
@include fontFace( #{$font-name}-Light, 300, normal );
/* Light Italic */
@include fontFace( #{$font-name}-LightIt, 300, italic );
/* Book */
@include fontFace( #{$font-name}-Book, 400, normal );
/* Book Italic */
@include fontFace( #{$font-name}-BookIt, 400, italic );
/* Regular */
@include fontFace( #{$font-name}-Regular, 500, normal );
/* Regular Italic */
@include fontFace( #{$font-name}-RegularIt, 500, italic );
/* Medium */
@include fontFace( #{$font-name}-Medium, 600, normal );
/* Medium Italic */
@include fontFace( #{$font-name}-MediumIt, 600, italic );
/* Bold */
@include fontFace( #{$font-name}-Bold, 700, normal );
/* Bold Italic */
@include fontFace( #{$font-name}-BoldIt, 700, italic );
/* Extra Bold */
@include fontFace( #{$font-name}-ExtraBold, 800, normal );
/* Extra Bold Italic */
@include fontFace( #{$font-name}-ExtraBoldIt, 800, italic );
/* Black */
@include fontFace( #{$font-name}-Black, 900, normal );
/* Black Italic */
@include fontFace( #{$font-name}-BlackIt, 900, italic );


// There's also an Extra Black

// /* Extra Black */
// @include fontFace( #{$font-name}-ExtraBlack, 900, normal );
// /* Extra Black Italic */
// @include fontFace( #{$font-name}-ExtraBlackIt, 900, italic );

mixin-fontface.scss

// ----------------------------------------
// Usage
// ----------------------------------------
// (1) Set 'variables' below to override the defaults
//
// (2) Include this mixin
// @import 'mixin-fontface';
// 
// (3) Add this line for each weight & style, preferably in separate scss files:
// @include fontFace( #{$font-name}<-weight>, <weight numbers>, <font style> );

// variables
$path-prefix: '../webfonts' !default;
$font-subfolder: '' !default;
$font-name: 'generic-font-name' !default;
$font-family: $font-name !default;
$font-formats: EOT WOFF SVG TTF !default; // EOT WOFF WOFF2 SVG OTF TTF

// append slash
@if $font-subfolder not "" {
  $font-subfolder: "#{$font-subfolder}/";
}

// subfolders for each font format
$EOT:   '#{$font-subfolder}EOT' !default;
$WOFF:  '#{$font-subfolder}WOFF' !default;
$WOFF2: '#{$font-subfolder}WOFF2' !default;
$OTF:   '#{$font-subfolder}OTF' !default;
$SVG:   '#{$font-subfolder}SVG' !default;
$TTF:   '#{$font-subfolder}TTF' !default;

// list to contain formats
$format-list: parseFontList($font-formats);

//  ----------------------------------------------
//  fontFace
//
//  Compiles to a font face rule.
//  Uses variables set above.
//  ----------------------------------------------
@mixin fontFace( $filename, $fw, $fs ) {
  // blank list to compile
  $font-list: ();
  // if format listed, add to compile list
  @if index($font-formats, 'EOT') {
    $font-list: append(
      $font-list, 
      unquote("url(#{$path-prefix}/#{$EOT}/#{$filename}.eot?#iefix) format('embedded-opentype')"), 
      comma
    );
  }
  @if index($font-formats, 'WOFF') {
    $font-list: append(
      $font-list, 
      unquote("url(#{$path-prefix}/#{$WOFF}/#{$filename}.woff) format('woff')"), 
      comma
    );
  }
  @if index($font-formats, 'WOFF2') {
    $font-list: append(
      $font-list, 
      unquote("url(#{$path-prefix}/#{$WOFF2}/#{$filename}.woff2) format('woff2'),"), 
      comma
    );
  }
  @if index($font-formats, 'SVG') {
    $font-list: append(
      $font-list, 
      unquote("url(#{$path-prefix}/#{$SVG}/#{$filename}.svg##{$font-name}) format('svg')"), 
      comma
    );
  }
  @if index($font-formats, 'TTF') {
    $font-list: append(
      $font-list, 
      unquote("url(#{$path-prefix}/#{$TTF}/#{$filename}.ttf) format('truetype')"), 
      comma
    );
  }
  @if index($font-formats, 'OTF') {  
    $font-list: append(
      $font-list, 
      unquote("url(#{$path-prefix}/#{$OTF}/#{$filename}.otf) format('opentype');"), 
      comma
    );
  }
  // create @font-face rule
  @font-face {
    font-family: $font-family;
    font-weight: $fw;
    font-style: $fs;
    src:
      $font-list
      ;
  }
}