Vectors / Graphics

Vectors + 
Freepik.com – https://www.freepik.com
Shutterstock.com – https://www.shutterstock.com
CreativeMarket.com – https://creativemarket.com
Vectorstock.com – https://www.vectorstock.com
Pixeden.com – https://www.pixeden.com
DepositPhotos.com – https://depositphotos.com
Graphic River – https://graphicriver.net
Graphic Burger – https://graphicburger.com
AlienValley – https://alienvalley.com

Icons
FlatIcon – https://www.flaticon.com
Iconshock – https://www.iconshock.com
IconPerk – https://www.iconperk.com

PSDs
Official PSDs.com – https://officialpsds.com – this site tends to have spam links overlaying downloads. be careful.

Inspiration
Pinterest
Etsy
Dribble
Behance