유용한 아이콘 모음

Free Flat Social Icons

http://tinktank.in/free-flat-social-icons/

http://speckyboy.com/2013/09/05/social-icon-sets/

free-flat-social-icons-master.zip

Freebie: Universal Themes Vector Icon Set (100 Icons, SVG)

http://speckyboy.com/2015/12/18/freebie-universal-themes-vector-icon-set/

100-Universal-themes-icons.zip

http://www.iconarchive.com/