kitfox.com

Instant Stairs is a Blender addon that adds two new options under the Add Mesh menu for generating staircases. Set a few parameters to instantly produce straight or spiral stairs in just a few clicks.

Normal Brush is a Blender addon that adds a control for adjusting mesh normals by stroking your model with a brush. It comes from kitfox.com and ships with documentation.

Parrot Lipsync is a Blender addon that automatically generates lip-synced keyframes from audio tracks. It works for both 2D and 3D animation and, using the Allosaurus engine, can be used with any language.