Sketchup
my.SketchUp is the core SketchUp modeler, tuned to work in modern web browsers. Draw, orbit, push-pull: make anything you can imagine in SketchUp, anytime you imagine it.
3D Modelling
3D Modelling for Games
A selection of resources for 3D games design.
TinkerCad
Tinkercad is a simple, online 3D design and 3D printing app for everyone.
SculptGL
SculptGL is a digital sculpting web app. If you want to download a standalone version, you can download it here (identical as the web version). SculptGL