1) 네이버 한글한글 아름답게
http://hangeul.naver.com/

2) 아이콘파인더
https://www.iconfinder.com

3) Colorion
http://material.colorion.co/popular

4) pixabay
https://pixabay.com/

5) subtle patterns
https://www.toptal.com/designers/subtlepatterns/

6) pixlr
https://pixlr.com/

7) soundjay
https://www.soundjay.com/