The plugin that offers a professional, for a free and open-source 3D computer graphics software toolset used for creating animated films, visual effects, art, 3D printed models, interactive 3D applications and video games,   3D modeling of what?
ManuelbastioniLAB ManuelbastioniLAB is a free and open source plug-in for Blender for the parametric 3D modeling of photorealistic humanoid characters.
Freestyle (software) Freestyle is a free, open source renderer for non-photorealistic line drawing from 3D scenes.