SpeedTree - SpeedTree is a powerful toolkit used to create 3D vegetation for video games, films, and animations.
Stet.io - Stet.io is a high-quality pixel management platform that allows editing the pictures with online commands or multiple options with real-time effects or filters.
Tree Studio - Easy 2D Tree Creation
AliveColors - AliveColors is comprehensive graphics and photo editing software for Windows and Mac.
Krita - Krita is a professional FREE and open source painting program. It is made by artists that want to seaffordable art tools for everyone. Concept art. texture and matte painters, illustrations and comics.
ImageForge - - ImageForge Standard Freeware Edition: