My version of the Gmod ponies for Blender, based on "Cheerilee's Gmod Ponies" package. Originals are licensed CC-BY and therefore re-uploaded legally. Improvements in my version include:
Version 3.0 (18-12-2012):
All ponies are rigged (apart from Luna and Celestia since they have different forms, will get to them later). Facial expressions can also be animated.
Old eyes replaced with deformed spheres, which allow pointing toward a specific look direction without changing form. The original eyes are also available on another layer.
Shared mesh data for all objects that use the same shape. This should reduce file / memory size and as well as make it easier to edit the ponies.
Pin vertex groups for manes and tails, allowing cloth simulation in animations (not for Luna and Celestia yet).
Subsurf all objects for higher quality, only visible at render time.
Version 3.1 (12-08-2013):
Rigged Celestia & Luna. Also give their mane and tail cloth pinning weights.
Reduced polygon count for excessively high-poly models.
Fix bones and weight paint errors in various places. Facial expressions are also much more flexible and configurable.
Bone constraints, to keep pose deformations within correct limits (disable if animating broken limbs).
Bone shapes (looks nicer and makes posing easier).
Default walk animation included (moves 1 blender unit per loop).
Optional freestyle configuration, allowing for original MLP-FiM lines and shading.