MasterpieceVR - Powerful VR sculpting & painting tool
Sculptura - 3D sculpting for everyone
Oculus Medium - Sculpt, model and paint in virtual reality on a 3D canvas.
Nomad Sculpt - Nomad is a sculpting & painting mobile app, available on Android and iOS.
A-Painter - Paint in VR in your Browser
PaintCube - Web-based 3D painting software