I needed to list all of the available icons from Font Awesome 4.2.0 in order to allow users to select one. The code for the selector was easy enough but parsing through the Font Awesome stylesheet to get all the icon class names took sometime to filter it out.
Since it ended up taking a lot of time out of my day, I thought I would add the code here for everyone to use.
<?php
$fontawesome_icons = array(
'fa fa-glass',
'fa fa-music',
'fa fa-search',
'fa fa-envelope-o',
'fa fa-heart',
'fa fa-star',
'fa fa-star-o',
'fa fa-user',
'fa fa-film',
'fa fa-th-large',
'fa fa-th',
'fa fa-th-list',
'fa fa-check',
'fa fa-remove',
'fa fa-close',
'fa fa-times',
'fa fa-search-plus',
'fa fa-search-minus',
'fa fa-power-off',
'fa fa-signal',
'fa fa-gear',
'fa fa-cog',
'fa fa-trash-o',
'fa fa-home',
'fa fa-file-o',
'fa fa-clock-o',
'fa fa-road',
'fa fa-download',
'fa fa-arrow-circle-o-down',
'fa fa-arrow-circle-o-up',
'fa fa-inbox',
'fa fa-play-circle-o',
'fa fa-rotate-right',
'fa fa-repeat',
'fa fa-refresh',
'fa fa-list-alt',
'fa fa-lock',
'fa fa-flag',
'fa fa-headphones',
'fa fa-volume-off',
'fa fa-volume-down',
'fa fa-volume-up',
'fa fa-qrcode',
'fa fa-barcode',
'fa fa-tag',
'fa fa-tags',
'fa fa-book',
'fa fa-bookmark',
'fa fa-print',
'fa fa-camera',
'fa fa-font',
'fa fa-bold',
'fa fa-italic',
'fa fa-text-height',
'fa fa-text-width',
'fa fa-align-left',
'fa fa-align-center',
'fa fa-align-right',
'fa fa-align-justify',
'fa fa-list',
'fa fa-dedent',
'fa fa-outdent',
'fa fa-indent',
'fa fa-video-camera',
'fa fa-photo',
'fa fa-image',
'fa fa-picture-o',
'fa fa-pencil',
'fa fa-map-marker',
'fa fa-adjust',
'fa fa-tint',
'fa fa-edit',
'fa fa-pencil-square-o',
'fa fa-share-square-o',
'fa fa-check-square-o',
'fa fa-arrows',
'fa fa-step-backward',
'fa fa-fast-backward',
'fa fa-backward',
'fa fa-play',
'fa fa-pause',
'fa fa-stop',
'fa fa-forward',
'fa fa-fast-forward',
'fa fa-step-forward',
'fa fa-eject',
'fa fa-chevron-left',
'fa fa-chevron-right',
'fa fa-plus-circle',
'fa fa-minus-circle',
'fa fa-times-circle',
'fa fa-check-circle',
'fa fa-question-circle',
'fa fa-info-circle',
'fa fa-crosshairs',
'fa fa-times-circle-o',
'fa fa-check-circle-o',
'fa fa-ban',
'fa fa-arrow-left',
'fa fa-arrow-right',
'fa fa-arrow-up',
'fa fa-arrow-down',
'fa fa-mail-forward',
'fa fa-share',
'fa fa-expand',
'fa fa-compress',
'fa fa-plus',
'fa fa-minus',
'fa fa-asterisk',
'fa fa-exclamation-circle',
'fa fa-gift',
'fa fa-leaf',
'fa fa-fire',
'fa fa-eye',
'fa fa-eye-slash',
'fa fa-warning',
'fa fa-exclamation-triangle',
'fa fa-plane',
'fa fa-calendar',
'fa fa-random',
'fa fa-comment',
'fa fa-magnet',
'fa fa-chevron-up',
'fa fa-chevron-down',
'fa fa-retweet',
'fa fa-shopping-cart',
'fa fa-folder',
'fa fa-folder-open',
'fa fa-arrows-v',
'fa fa-arrows-h',
'fa fa-bar-chart-o',
'fa fa-bar-chart',
'fa fa-twitter-square',
'fa fa-facebook-square',
'fa fa-camera-retro',
'fa fa-key',
'fa fa-gears',
'fa fa-cogs',
'fa fa-comments',
'fa fa-thumbs-o-up',
'fa fa-thumbs-o-down',
'fa fa-star-half',
'fa fa-heart-o',
'fa fa-sign-out',
'fa fa-linkedin-square',
'fa fa-thumb-tack',
'fa fa-external-link',
'fa fa-sign-in',
'fa fa-trophy',
'fa fa-github-square',
'fa fa-upload',
'fa fa-lemon-o',
'fa fa-phone',
'fa fa-square-o',
'fa fa-bookmark-o',
'fa fa-phone-square',
'fa fa-twitter',
'fa fa-facebook',
'fa fa-github',
'fa fa-unlock',
'fa fa-credit-card',
'fa fa-rss',
'fa fa-hdd-o',
'fa fa-bullhorn',
'fa fa-bell',
'fa fa-certificate',
'fa fa-hand-o-right',
'fa fa-hand-o-left',
'fa fa-hand-o-up',
'fa fa-hand-o-down',
'fa fa-arrow-circle-left',
'fa fa-arrow-circle-right',
'fa fa-arrow-circle-up',
'fa fa-arrow-circle-down',
'fa fa-globe',
'fa fa-wrench',
'fa fa-tasks',
'fa fa-filter',
'fa fa-briefcase',
'fa fa-arrows-alt',
'fa fa-group',
'fa fa-users',
'fa fa-chain',
'fa fa-link',
'fa fa-cloud',
'fa fa-flask',
'fa fa-cut',
'fa fa-scissors',
'fa fa-copy',
'fa fa-files-o',
'fa fa-paperclip',
'fa fa-save',
'fa fa-floppy-o',
'fa fa-square',
'fa fa-navicon',
'fa fa-reorder',
'fa fa-bars',
'fa fa-list-ul',
'fa fa-list-ol',
'fa fa-strikethrough',
'fa fa-underline',
'fa fa-table',
'fa fa-magic',
'fa fa-truck',
'fa fa-pinterest',
'fa fa-pinterest-square',
'fa fa-google-plus-square',
'fa fa-google-plus',
'fa fa-money',
'fa fa-caret-down',
'fa fa-caret-up',
'fa fa-caret-left',
'fa fa-caret-right',
'fa fa-columns',
'fa fa-unsorted',
'fa fa-sort',
'fa fa-sort-down',
'fa fa-sort-desc',
'fa fa-sort-up',
'fa fa-sort-asc',
'fa fa-envelope',
'fa fa-linkedin',
'fa fa-rotate-left',
'fa fa-undo',
'fa fa-legal',
'fa fa-gavel',
'fa fa-dashboard',
'fa fa-tachometer',
'fa fa-comment-o',
'fa fa-comments-o',
'fa fa-flash',
'fa fa-bolt',
'fa fa-sitemap',
'fa fa-umbrella',
'fa fa-paste',
'fa fa-clipboard',
'fa fa-lightbulb-o',
'fa fa-exchange',
'fa fa-cloud-download',
'fa fa-cloud-upload',
'fa fa-user-md',
'fa fa-stethoscope',
'fa fa-suitcase',
'fa fa-bell-o',
'fa fa-coffee',
'fa fa-cutlery',
'fa fa-file-text-o',
'fa fa-building-o',
'fa fa-hospital-o',
'fa fa-ambulance',
'fa fa-medkit',
'fa fa-fighter-jet',
'fa fa-beer',
'fa fa-h-square',
'fa fa-plus-square',
'fa fa-angle-double-left',
'fa fa-angle-double-right',
'fa fa-angle-double-up',
'fa fa-angle-double-down',
'fa fa-angle-left',
'fa fa-angle-right',
'fa fa-angle-up',
'fa fa-angle-down',
'fa fa-desktop',
'fa fa-laptop',
'fa fa-tablet',
'fa fa-mobile-phone',
'fa fa-mobile',
'fa fa-circle-o',
'fa fa-quote-left',
'fa fa-quote-right',
'fa fa-spinner',
'fa fa-circle',
'fa fa-mail-reply',
'fa fa-reply',
'fa fa-github-alt',
'fa fa-folder-o',
'fa fa-folder-open-o',
'fa fa-smile-o',
'fa fa-frown-o',
'fa fa-meh-o',
'fa fa-gamepad',
'fa fa-keyboard-o',
'fa fa-flag-o',
'fa fa-flag-checkered',
'fa fa-terminal',
'fa fa-code',
'fa fa-mail-reply-all',
'fa fa-reply-all',
'fa fa-star-half-empty',
'fa fa-star-half-full',
'fa fa-star-half-o',
'fa fa-location-arrow',
'fa fa-crop',
'fa fa-code-fork',
'fa fa-unlink',
'fa fa-chain-broken',
'fa fa-question',
'fa fa-info',
'fa fa-exclamation',
'fa fa-superscript',
'fa fa-subscript',
'fa fa-eraser',
'fa fa-puzzle-piece',
'fa fa-microphone',
'fa fa-microphone-slash',
'fa fa-shield',
'fa fa-calendar-o',
'fa fa-fire-extinguisher',
'fa fa-rocket',
'fa fa-maxcdn',
'fa fa-chevron-circle-left',
'fa fa-chevron-circle-right',
'fa fa-chevron-circle-up',
'fa fa-chevron-circle-down',
'fa fa-html5',
'fa fa-css3',
'fa fa-anchor',
'fa fa-unlock-alt',
'fa fa-bullseye',
'fa fa-ellipsis-h',
'fa fa-ellipsis-v',
'fa fa-rss-square',
'fa fa-play-circle',
'fa fa-ticket',
'fa fa-minus-square',
'fa fa-minus-square-o',
'fa fa-level-up',
'fa fa-level-down',
'fa fa-check-square',
'fa fa-pencil-square',
'fa fa-external-link-square',
'fa fa-share-square',
'fa fa-compass',
'fa fa-toggle-down',
'fa fa-caret-square-o-down',
'fa fa-toggle-up',
'fa fa-caret-square-o-up',
'fa fa-toggle-right',
'fa fa-caret-square-o-right',
'fa fa-euro',
'fa fa-eur',
'fa fa-gbp',
'fa fa-dollar',
'fa fa-usd',
'fa fa-rupee',
'fa fa-inr',
'fa fa-cny',
'fa fa-rmb',
'fa fa-yen',
'fa fa-jpy',
'fa fa-ruble',
'fa fa-rouble',
'fa fa-rub',
'fa fa-won',
'fa fa-krw',
'fa fa-bitcoin',
'fa fa-btc',
'fa fa-file',
'fa fa-file-text',
'fa fa-sort-alpha-asc',
'fa fa-sort-alpha-desc',
'fa fa-sort-amount-asc',
'fa fa-sort-amount-desc',
'fa fa-sort-numeric-asc',
'fa fa-sort-numeric-desc',
'fa fa-thumbs-up',
'fa fa-thumbs-down',
'fa fa-youtube-square',
'fa fa-youtube',
'fa fa-xing',
'fa fa-xing-square',
'fa fa-youtube-play',
'fa fa-dropbox',
'fa fa-stack-overflow',
'fa fa-instagram',
'fa fa-flickr',
'fa fa-adn',
'fa fa-bitbucket',
'fa fa-bitbucket-square',
'fa fa-tumblr',
'fa fa-tumblr-square',
'fa fa-long-arrow-down',
'fa fa-long-arrow-up',
'fa fa-long-arrow-left',
'fa fa-long-arrow-right',
'fa fa-apple',
'fa fa-windows',
'fa fa-android',
'fa fa-linux',
'fa fa-dribbble',
'fa fa-skype',
'fa fa-foursquare',
'fa fa-trello',
'fa fa-female',
'fa fa-male',
'fa fa-gittip',
'fa fa-sun-o',
'fa fa-moon-o',
'fa fa-archive',
'fa fa-bug',
'fa fa-vk',
'fa fa-weibo',
'fa fa-renren',
'fa fa-pagelines',
'fa fa-stack-exchange',
'fa fa-arrow-circle-o-right',
'fa fa-arrow-circle-o-left',
'fa fa-toggle-left',
'fa fa-caret-square-o-left',
'fa fa-dot-circle-o',
'fa fa-wheelchair',
'fa fa-vimeo-square',
'fa fa-turkish-lira',
'fa fa-try',
'fa fa-plus-square-o',
'fa fa-space-shuttle',
'fa fa-slack',
'fa fa-envelope-square',
'fa fa-wordpress',
'fa fa-openid',
'fa fa-institution',
'fa fa-bank',
'fa fa-university',
'fa fa-mortar-board',
'fa fa-graduation-cap',
'fa fa-yahoo',
'fa fa-google',
'fa fa-reddit',
'fa fa-reddit-square',
'fa fa-stumbleupon-circle',
'fa fa-stumbleupon',
'fa fa-delicious',
'fa fa-digg',
'fa fa-pied-piper',
'fa fa-pied-piper-alt',
'fa fa-drupal',
'fa fa-joomla',
'fa fa-language',
'fa fa-fax',
'fa fa-building',
'fa fa-child',
'fa fa-paw',
'fa fa-spoon',
'fa fa-cube',
'fa fa-cubes',
'fa fa-behance',
'fa fa-behance-square',
'fa fa-steam',
'fa fa-steam-square',
'fa fa-recycle',
'fa fa-automobile',
'fa fa-car',
'fa fa-cab',
'fa fa-taxi',
'fa fa-tree',
'fa fa-spotify',
'fa fa-deviantart',
'fa fa-soundcloud',
'fa fa-database',
'fa fa-file-pdf-o',
'fa fa-file-word-o',
'fa fa-file-excel-o',
'fa fa-file-powerpoint-o',
'fa fa-file-photo-o',
'fa fa-file-picture-o',
'fa fa-file-image-o',
'fa fa-file-zip-o',
'fa fa-file-archive-o',
'fa fa-file-sound-o',
'fa fa-file-audio-o',
'fa fa-file-movie-o',
'fa fa-file-video-o',
'fa fa-file-code-o',
'fa fa-vine',
'fa fa-codepen',
'fa fa-jsfiddle',
'fa fa-life-bouy',
'fa fa-life-buoy',
'fa fa-life-saver',
'fa fa-support',
'fa fa-life-ring',
'fa fa-circle-o-notch',
'fa fa-ra',
'fa fa-rebel',
'fa fa-ge',
'fa fa-empire',
'fa fa-git-square',
'fa fa-git',
'fa fa-hacker-news',
'fa fa-tencent-weibo',
'fa fa-qq',
'fa fa-wechat',
'fa fa-weixin',
'fa fa-send',
'fa fa-paper-plane',
'fa fa-send-o',
'fa fa-paper-plane-o',
'fa fa-history',
'fa fa-circle-thin',
'fa fa-header',
'fa fa-paragraph',
'fa fa-sliders',
'fa fa-share-alt',
'fa fa-share-alt-square',
'fa fa-bomb',
'fa fa-soccer-ball-o',
'fa fa-futbol-o',
'fa fa-tty',
'fa fa-binoculars',
'fa fa-plug',
'fa fa-slideshare',
'fa fa-twitch',
'fa fa-yelp',
'fa fa-newspaper-o',
'fa fa-wifi',
'fa fa-calculator',
'fa fa-paypal',
'fa fa-google-wallet',
'fa fa-cc-visa',
'fa fa-cc-mastercard',
'fa fa-cc-discover',
'fa fa-cc-amex',
'fa fa-cc-paypal',
'fa fa-cc-stripe',
'fa fa-bell-slash',
'fa fa-bell-slash-o',
'fa fa-trash',
'fa fa-copyright',
'fa fa-at',
'fa fa-eyedropper',
'fa fa-paint-brush',
'fa fa-birthday-cake',
'fa fa-area-chart',
'fa fa-pie-chart',
'fa fa-line-chart',
'fa fa-lastfm',
'fa fa-lastfm-square',
'fa fa-toggle-off',
'fa fa-toggle-on',
'fa fa-bicycle',
'fa fa-bus',
'fa fa-ioxhost',
'fa fa-angellist',
'fa fa-cc',
'fa fa-shekel',
'fa fa-sheqel',
'fa fa-ils',
'fa fa-meanpath',
);
Having this array available made it a whole lot easier to start messing around with creating a visual way of selecting an icon. If you use Arcade for WordPress you can see this array in action through the Customizer and Icon & Text widget.
