I have for a long time meant to upload folding instructions for origami ponies which I made a while ago. Somehow I kept forgetting about doing this.  
These instructions lay out how to fold a simple origami pony (earthpony, unicorn, pegasus or alicorn) from a square sheet of paper. It is based on the so called “bird base” (one of the most frequent starting point for all kinds of origami figures).  
Unlike many origami figures this one requires a few cuts. If you want to you can create more detailed manes for your pony figures with a few more cuts along the paper edges folded to the inside of the pony’s head.  
By varying the position of the legs and (in case of pegasi or alicorns) wings you can create a wide variety of postures for your origami ponies. Here are a few examples.  
Enjoy folding them ;-)