You can use a set of 400+ icons from Font Awesome

<i class="fa fa-heart"></i> fa-heart

Result:   fa-heart

fa-adjust[&#xf042;]
fa-adn[&#xf170;]
fa-align-center[&#xf037;]
fa-align-justify[&#xf039;]
fa-align-left[&#xf036;]
fa-align-right[&#xf038;]
fa-ambulance[&#xf0f9;]
fa-anchor[&#xf13d;]
fa-android[&#xf17b;]
fa-angle-double-down[&#xf103;]
fa-angle-double-left[&#xf100;]
fa-angle-double-right[&#xf101;]
fa-angle-double-up[&#xf102;]
fa-angle-down[&#xf107;]
fa-angle-left[&#xf104;]
fa-angle-right[&#xf105;]
fa-angle-up[&#xf106;]
fa-apple[&#xf179;]
fa-archive[&#xf187;]
fa-arrow-circle-down[&#xf0ab;]
fa-arrow-circle-left[&#xf0a8;]
fa-arrow-circle-o-down[&#xf01a;]
fa-arrow-circle-o-left[&#xf190;]
fa-arrow-circle-o-right[&#xf18e;]
fa-arrow-circle-o-up[&#xf01b;]
fa-arrow-circle-right[&#xf0a9;]
fa-arrow-circle-up[&#xf0aa;]
fa-arrow-down[&#xf063;]
fa-arrow-left[&#xf060;]
fa-arrow-right[&#xf061;]
fa-arrow-up[&#xf062;]
fa-arrows[&#xf047;]
fa-arrows-alt[&#xf0b2;]
fa-arrows-h[&#xf07e;]
fa-arrows-v[&#xf07d;]
fa-asterisk[&#xf069;]
fa-automobile(alias) [&#xf1b9;]
fa-backward[&#xf04a;]
fa-ban[&#xf05e;]
fa-bank(alias) [&#xf19c;]
fa-bar-chart-o[&#xf080;]
fa-barcode[&#xf02a;]
fa-bars[&#xf0c9;]
fa-beer[&#xf0fc;]
fa-behance[&#xf1b4;]
fa-behance-square[&#xf1b5;]
fa-bell[&#xf0f3;]
fa-bell-o[&#xf0a2;]
fa-bitbucket[&#xf171;]
fa-bitbucket-square[&#xf172;]
fa-bitcoin(alias) [&#xf15a;]
fa-bold[&#xf032;]
fa-bolt[&#xf0e7;]
fa-bomb[&#xf1e2;]
fa-book[&#xf02d;]
fa-bookmark[&#xf02e;]
fa-bookmark-o[&#xf097;]
fa-briefcase[&#xf0b1;]
fa-btc[&#xf15a;]
fa-bug[&#xf188;]
fa-building[&#xf1ad;]
fa-building-o[&#xf0f7;]
fa-bullhorn[&#xf0a1;]
fa-bullseye[&#xf140;]
fa-cab(alias) [&#xf1ba;]
fa-calendar[&#xf073;]
fa-calendar-o[&#xf133;]
fa-camera[&#xf030;]
fa-camera-retro[&#xf083;]
fa-car[&#xf1b9;]
fa-caret-down[&#xf0d7;]
fa-caret-left[&#xf0d9;]
fa-caret-right[&#xf0da;]
fa-caret-square-o-down[&#xf150;]
fa-caret-square-o-left[&#xf191;]
fa-caret-square-o-right[&#xf152;]
fa-caret-square-o-up[&#xf151;]
fa-caret-up[&#xf0d8;]
fa-certificate[&#xf0a3;]
fa-chain(alias) [&#xf0c1;]
fa-chain-broken[&#xf127;]
fa-check[&#xf00c;]
fa-check-circle[&#xf058;]
fa-check-circle-o[&#xf05d;]
fa-check-square[&#xf14a;]
fa-check-square-o[&#xf046;]
fa-chevron-circle-down[&#xf13a;]
fa-chevron-circle-left[&#xf137;]
fa-chevron-circle-right[&#xf138;]
fa-chevron-circle-up[&#xf139;]
fa-chevron-down[&#xf078;]
fa-chevron-left[&#xf053;]
fa-chevron-right[&#xf054;]
fa-chevron-up[&#xf077;]
fa-child[&#xf1ae;]
fa-circle[&#xf111;]
fa-circle-o[&#xf10c;]
fa-circle-o-notch[&#xf1ce;]
fa-circle-thin[&#xf1db;]
fa-clipboard[&#xf0ea;]
fa-clock-o[&#xf017;]
fa-cloud[&#xf0c2;]
fa-cloud-download[&#xf0ed;]
fa-cloud-upload[&#xf0ee;]
fa-cny(alias) [&#xf157;]
fa-code[&#xf121;]
fa-code-fork[&#xf126;]
fa-codepen[&#xf1cb;]
fa-coffee[&#xf0f4;]
fa-cog[&#xf013;]
fa-cogs[&#xf085;]
fa-columns[&#xf0db;]
fa-comment[&#xf075;]
fa-comment-o[&#xf0e5;]
fa-comments[&#xf086;]
fa-comments-o[&#xf0e6;]
fa-compass[&#xf14e;]
fa-compress[&#xf066;]
fa-copy(alias) [&#xf0c5;]
fa-credit-card[&#xf09d;]
fa-crop[&#xf125;]
fa-crosshairs[&#xf05b;]
fa-css3[&#xf13c;]
fa-cube[&#xf1b2;]
fa-cubes[&#xf1b3;]
fa-cut(alias) [&#xf0c4;]
fa-cutlery[&#xf0f5;]
fa-dashboard(alias) [&#xf0e4;]
fa-database[&#xf1c0;]
fa-dedent(alias) [&#xf03b;]
fa-delicious[&#xf1a5;]
fa-desktop[&#xf108;]
fa-deviantart[&#xf1bd;]
fa-digg[&#xf1a6;]
fa-dollar(alias) [&#xf155;]
fa-dot-circle-o[&#xf192;]
fa-download[&#xf019;]
fa-dribbble[&#xf17d;]
fa-dropbox[&#xf16b;]
fa-drupal[&#xf1a9;]
fa-edit(alias) [&#xf044;]
fa-eject[&#xf052;]
fa-ellipsis-h[&#xf141;]
fa-ellipsis-v[&#xf142;]
fa-empire[&#xf1d1;]
fa-envelope[&#xf0e0;]
fa-envelope-o[&#xf003;]
fa-envelope-square[&#xf199;]
fa-eraser[&#xf12d;]
fa-eur[&#xf153;]
fa-euro(alias) [&#xf153;]
fa-exchange[&#xf0ec;]
fa-exclamation[&#xf12a;]
fa-exclamation-circle[&#xf06a;]
fa-exclamation-triangle[&#xf071;]
fa-expand[&#xf065;]
fa-external-link[&#xf08e;]
fa-external-link-square[&#xf14c;]
fa-eye[&#xf06e;]
fa-eye-slash[&#xf070;]
fa-facebook[&#xf09a;]
fa-facebook-square[&#xf082;]
fa-fast-backward[&#xf049;]
fa-fast-forward[&#xf050;]
fa-fax[&#xf1ac;]
fa-female[&#xf182;]
fa-fighter-jet[&#xf0fb;]
fa-file[&#xf15b;]
fa-file-archive-o[&#xf1c6;]
fa-file-audio-o[&#xf1c7;]
fa-file-code-o[&#xf1c9;]
fa-file-excel-o[&#xf1c3;]
fa-file-image-o[&#xf1c5;]
fa-file-movie-o(alias) [&#xf1c8;]
fa-file-o[&#xf016;]
fa-file-pdf-o[&#xf1c1;]
fa-file-photo-o(alias) [&#xf1c5;]
fa-file-picture-o(alias) [&#xf1c5;]
fa-file-powerpoint-o[&#xf1c4;]
fa-file-sound-o(alias) [&#xf1c7;]
fa-file-text[&#xf15c;]
fa-file-text-o[&#xf0f6;]
fa-file-video-o[&#xf1c8;]
fa-file-word-o[&#xf1c2;]
fa-file-zip-o(alias) [&#xf1c6;]
fa-files-o[&#xf0c5;]
fa-film[&#xf008;]
fa-filter[&#xf0b0;]
fa-fire[&#xf06d;]
fa-fire-extinguisher[&#xf134;]
fa-flag[&#xf024;]
fa-flag-checkered[&#xf11e;]
fa-flag-o[&#xf11d;]
fa-flash(alias) [&#xf0e7;]
fa-flask[&#xf0c3;]
fa-flickr[&#xf16e;]
fa-floppy-o[&#xf0c7;]
fa-folder[&#xf07b;]
fa-folder-o[&#xf114;]
fa-folder-open[&#xf07c;]
fa-folder-open-o[&#xf115;]
fa-font[&#xf031;]
fa-forward[&#xf04e;]
fa-foursquare[&#xf180;]
fa-frown-o[&#xf119;]
fa-gamepad[&#xf11b;]
fa-gavel[&#xf0e3;]
fa-gbp[&#xf154;]
fa-ge(alias) [&#xf1d1;]
fa-gear(alias) [&#xf013;]
fa-gears(alias) [&#xf085;]
fa-gift[&#xf06b;]
fa-git[&#xf1d3;]
fa-git-square[&#xf1d2;]
fa-github[&#xf09b;]
fa-github-alt[&#xf113;]
fa-github-square[&#xf092;]
fa-gittip[&#xf184;]
fa-glass[&#xf000;]
fa-globe[&#xf0ac;]
fa-google[&#xf1a0;]
fa-google-plus[&#xf0d5;]
fa-google-plus-square[&#xf0d4;]
fa-graduation-cap[&#xf19d;]
fa-group(alias) [&#xf0c0;]
fa-h-square[&#xf0fd;]
fa-hacker-news[&#xf1d4;]
fa-hand-o-down[&#xf0a7;]
fa-hand-o-left[&#xf0a5;]
fa-hand-o-right[&#xf0a4;]
fa-hand-o-up[&#xf0a6;]
fa-hdd-o[&#xf0a0;]
fa-header[&#xf1dc;]
fa-headphones[&#xf025;]
fa-heart[&#xf004;]
fa-heart-o[&#xf08a;]
fa-history[&#xf1da;]
fa-home[&#xf015;]
fa-hospital-o[&#xf0f8;]
fa-html5[&#xf13b;]
fa-image(alias) [&#xf03e;]
fa-inbox[&#xf01c;]
fa-indent[&#xf03c;]
fa-info[&#xf129;]
fa-info-circle[&#xf05a;]
fa-inr[&#xf156;]
fa-instagram[&#xf16d;]
fa-institution(alias) [&#xf19c;]
fa-italic[&#xf033;]
fa-joomla[&#xf1aa;]
fa-jpy[&#xf157;]
fa-jsfiddle[&#xf1cc;]
fa-key[&#xf084;]
fa-keyboard-o[&#xf11c;]
fa-krw[&#xf159;]
fa-language[&#xf1ab;]
fa-laptop[&#xf109;]
fa-leaf[&#xf06c;]
fa-legal(alias) [&#xf0e3;]
fa-lemon-o[&#xf094;]
fa-level-down[&#xf149;]
fa-level-up[&#xf148;]
fa-life-bouy(alias) [&#xf1cd;]
fa-life-ring[&#xf1cd;]
fa-life-saver(alias) [&#xf1cd;]
fa-lightbulb-o[&#xf0eb;]
fa-link[&#xf0c1;]
fa-linkedin[&#xf0e1;]
fa-linkedin-square[&#xf08c;]
fa-linux[&#xf17c;]
fa-list[&#xf03a;]
fa-list-alt[&#xf022;]
fa-list-ol[&#xf0cb;]
fa-list-ul[&#xf0ca;]
fa-location-arrow[&#xf124;]
fa-lock[&#xf023;]
fa-long-arrow-down[&#xf175;]
fa-long-arrow-left[&#xf177;]
fa-long-arrow-right[&#xf178;]
fa-long-arrow-up[&#xf176;]
fa-magic[&#xf0d0;]
fa-magnet[&#xf076;]
fa-mail-forward(alias) [&#xf064;]
fa-mail-reply(alias) [&#xf112;]
fa-mail-reply-all(alias) [&#xf122;]
fa-male[&#xf183;]
fa-map-marker[&#xf041;]
fa-maxcdn[&#xf136;]
fa-medkit[&#xf0fa;]
fa-meh-o[&#xf11a;]
fa-microphone[&#xf130;]
fa-microphone-slash[&#xf131;]
fa-minus[&#xf068;]
fa-minus-circle[&#xf056;]
fa-minus-square[&#xf146;]
fa-minus-square-o[&#xf147;]
fa-mobile[&#xf10b;]
fa-mobile-phone(alias) [&#xf10b;]
fa-money[&#xf0d6;]
fa-moon-o[&#xf186;]
fa-mortar-board(alias) [&#xf19d;]
fa-music[&#xf001;]
fa-navicon(alias) [&#xf0c9;]
fa-openid[&#xf19b;]
fa-outdent[&#xf03b;]
fa-pagelines[&#xf18c;]
fa-paper-plane[&#xf1d8;]
fa-paper-plane-o[&#xf1d9;]
fa-paperclip[&#xf0c6;]
fa-paragraph[&#xf1dd;]
fa-paste(alias) [&#xf0ea;]
fa-pause[&#xf04c;]
fa-paw[&#xf1b0;]
fa-pencil[&#xf040;]
fa-pencil-square[&#xf14b;]
fa-pencil-square-o[&#xf044;]
fa-phone[&#xf095;]
fa-phone-square[&#xf098;]
fa-photo(alias) [&#xf03e;]
fa-picture-o[&#xf03e;]
fa-pied-piper[&#xf1a7;]
fa-pied-piper-alt[&#xf1a8;]
fa-pied-piper-square(alias) [&#xf1a7;]
fa-pinterest[&#xf0d2;]
fa-pinterest-square[&#xf0d3;]
fa-plane[&#xf072;]
fa-play[&#xf04b;]
fa-play-circle[&#xf144;]
fa-play-circle-o[&#xf01d;]
fa-plus[&#xf067;]
fa-plus-circle[&#xf055;]
fa-plus-square[&#xf0fe;]
fa-plus-square-o[&#xf196;]
fa-power-off[&#xf011;]
fa-print[&#xf02f;]
fa-puzzle-piece[&#xf12e;]
fa-qq[&#xf1d6;]
fa-qrcode[&#xf029;]
fa-question[&#xf128;]
fa-question-circle[&#xf059;]
fa-quote-left[&#xf10d;]
fa-quote-right[&#xf10e;]
fa-ra(alias) [&#xf1d0;]
fa-random[&#xf074;]
fa-rebel[&#xf1d0;]
fa-recycle[&#xf1b8;]
fa-reddit[&#xf1a1;]
fa-reddit-square[&#xf1a2;]
fa-refresh[&#xf021;]
fa-renren[&#xf18b;]
fa-reorder(alias) [&#xf0c9;]
fa-repeat[&#xf01e;]
fa-reply[&#xf112;]
fa-reply-all[&#xf122;]
fa-retweet[&#xf079;]
fa-rmb(alias) [&#xf157;]
fa-road[&#xf018;]
fa-rocket[&#xf135;]
fa-rotate-left(alias) [&#xf0e2;]
fa-rotate-right(alias) [&#xf01e;]
fa-rouble(alias) [&#xf158;]
fa-rss[&#xf09e;]
fa-rss-square[&#xf143;]
fa-rub[&#xf158;]
fa-ruble(alias) [&#xf158;]
fa-rupee(alias) [&#xf156;]
fa-save(alias) [&#xf0c7;]
fa-scissors[&#xf0c4;]
fa-search[&#xf002;]
fa-search-minus[&#xf010;]
fa-search-plus[&#xf00e;]
fa-send(alias) [&#xf1d8;]
fa-send-o(alias) [&#xf1d9;]
fa-share[&#xf064;]
fa-share-alt[&#xf1e0;]
fa-share-alt-square[&#xf1e1;]
fa-share-square[&#xf14d;]
fa-share-square-o[&#xf045;]
fa-shield[&#xf132;]
fa-shopping-cart[&#xf07a;]
fa-sign-in[&#xf090;]
fa-sign-out[&#xf08b;]
fa-signal[&#xf012;]
fa-sitemap[&#xf0e8;]
fa-skype[&#xf17e;]
fa-slack[&#xf198;]
fa-sliders[&#xf1de;]
fa-smile-o[&#xf118;]
fa-sort[&#xf0dc;]
fa-sort-alpha-asc[&#xf15d;]
fa-sort-alpha-desc[&#xf15e;]
fa-sort-amount-asc[&#xf160;]
fa-sort-amount-desc[&#xf161;]
fa-sort-asc[&#xf0de;]
fa-sort-desc[&#xf0dd;]
fa-sort-down(alias) [&#xf0dd;]
fa-sort-numeric-asc[&#xf162;]
fa-sort-numeric-desc[&#xf163;]
fa-sort-up(alias) [&#xf0de;]
fa-soundcloud[&#xf1be;]
fa-space-shuttle[&#xf197;]
fa-spinner[&#xf110;]
fa-spoon[&#xf1b1;]
fa-spotify[&#xf1bc;]
fa-square[&#xf0c8;]
fa-square-o[&#xf096;]
fa-stack-exchange[&#xf18d;]
fa-stack-overflow[&#xf16c;]
fa-star[&#xf005;]
fa-star-half[&#xf089;]
fa-star-half-empty(alias) [&#xf123;]
fa-star-half-full(alias) [&#xf123;]
fa-star-half-o[&#xf123;]
fa-star-o[&#xf006;]
fa-steam[&#xf1b6;]
fa-steam-square[&#xf1b7;]
fa-step-backward[&#xf048;]
fa-step-forward[&#xf051;]
fa-stethoscope[&#xf0f1;]
fa-stop[&#xf04d;]
fa-strikethrough[&#xf0cc;]
fa-stumbleupon[&#xf1a4;]
fa-stumbleupon-circle[&#xf1a3;]
fa-subscript[&#xf12c;]
fa-suitcase[&#xf0f2;]
fa-sun-o[&#xf185;]
fa-superscript[&#xf12b;]
fa-support(alias) [&#xf1cd;]
fa-table[&#xf0ce;]
fa-tablet[&#xf10a;]
fa-tachometer[&#xf0e4;]
fa-tag[&#xf02b;]
fa-tags[&#xf02c;]
fa-tasks[&#xf0ae;]
fa-taxi[&#xf1ba;]
fa-tencent-weibo[&#xf1d5;]
fa-terminal[&#xf120;]
fa-text-height[&#xf034;]
fa-text-width[&#xf035;]
fa-th[&#xf00a;]
fa-th-large[&#xf009;]
fa-th-list[&#xf00b;]
fa-thumb-tack[&#xf08d;]
fa-thumbs-down[&#xf165;]
fa-thumbs-o-down[&#xf088;]
fa-thumbs-o-up[&#xf087;]
fa-thumbs-up[&#xf164;]
fa-ticket[&#xf145;]
fa-times[&#xf00d;]
fa-times-circle[&#xf057;]
fa-times-circle-o[&#xf05c;]
fa-tint[&#xf043;]
fa-toggle-down(alias) [&#xf150;]
fa-toggle-left(alias) [&#xf191;]
fa-toggle-right(alias) [&#xf152;]
fa-toggle-up(alias) [&#xf151;]
fa-trash-o[&#xf014;]
fa-tree[&#xf1bb;]
fa-trello[&#xf181;]
fa-trophy[&#xf091;]
fa-truck[&#xf0d1;]
fa-try[&#xf195;]
fa-tumblr[&#xf173;]
fa-tumblr-square[&#xf174;]
fa-turkish-lira(alias) [&#xf195;]
fa-twitter[&#xf099;]
fa-twitter-square[&#xf081;]
fa-umbrella[&#xf0e9;]
fa-underline[&#xf0cd;]
fa-undo[&#xf0e2;]
fa-university[&#xf19c;]
fa-unlink(alias) [&#xf127;]
fa-unlock[&#xf09c;]
fa-unlock-alt[&#xf13e;]
fa-unsorted(alias) [&#xf0dc;]
fa-upload[&#xf093;]
fa-usd[&#xf155;]
fa-user[&#xf007;]
fa-user-md[&#xf0f0;]
fa-users[&#xf0c0;]
fa-video-camera[&#xf03d;]
fa-vimeo-square[&#xf194;]
fa-vine[&#xf1ca;]
fa-vk[&#xf189;]
fa-volume-down[&#xf027;]
fa-volume-off[&#xf026;]
fa-volume-up[&#xf028;]
fa-warning(alias) [&#xf071;]
fa-wechat(alias) [&#xf1d7;]
fa-weibo[&#xf18a;]
fa-weixin[&#xf1d7;]
fa-wheelchair[&#xf193;]
fa-windows[&#xf17a;]
fa-won(alias) [&#xf159;]
fa-wordpress[&#xf19a;]
fa-wrench[&#xf0ad;]
fa-xing[&#xf168;]
fa-xing-square[&#xf169;]
fa-yahoo[&#xf19e;]
fa-yen(alias) [&#xf157;]
fa-youtube[&#xf167;]
fa-youtube-play[&#xf16a;]
fa-youtube-square[&#xf166;]