DeviantArt - deviantART was created to entertain, inspire, and empower the artist in all of us.
Figma - Team-based interface design, Figma lets you collaborate on designs in real time.
Brush Ninja - Hand-drawn Animated Gif Creator
Invision - Prototyping and collaboration for design teams
pixiv - pixiv is an illustration community service where you can post and enjoy creative work. A large variety of work is uploaded, and user-organized contests are frequently held as well.
Sketch - Professional digital design for Mac.