Invision - Prototyping and collaboration for design teams
Priime - Edit photos with the styles of the world's top photographers. Smart suggestions, fast editing, and inspiring collections.
Savahapp - The all-in-one design sharing, collaboration, workflow and app prototyping platform
Good Free Photos - Large free stock photo site with thousands of public photos
Pastel - Sticky note-based feedback collection tool for live websites
Skuawk Public Domain Photos - A large collection of free and artistically loud photos