You can draft your own patterns on ponies like on a person, if you want! Tape, scraps of thin cloth or even paper towels, a pencil that marks well on the tape, small sharp scissors, and a common pony to model are all you need. It's handy if the pony is bald so you don't have hair in the way (in fact, bait ponies are great because you won't need to worry about pencil marks), but you can just braid it up snugly.
Think about pony clothes as a variety of cylinders sticking out of each other. Just start wrapping the fabric or paper towels around, tape them on, and do light pencil sketches around where you think a sleeve seam or a neck hole or the waistline of a coat would go. Cut slashes up to these lines to get the cloth to conform neatly to the pony.
Cut though the tape at seam lines until you can spread the cloth back out flat. You can reinforce paper towels with more tape. The point is to work back and forth between the 3D surface of the pony and the flat surface of a table. You'll start to build an idea in your mind of how pony patterns look when laid out flat, and you can begin to try different seam placement to shape your garment, and experiment with darts (for beginners: triangular wedges removed that help turn a flat surface into a curved or conical one).
Try cutting the holes for the legs and trying the pattern back out on the pony. Not in the right place? Trim away a bit more cloth. Hole too big? Make a new edge out of tape and then apply a little tissue to the back when you don't want to be sticky anymore. Pattern getting too bulky and ugly? Cut off any unneeded bits and trace it out again on a new piece. Remember, at this scale, the little extra edge added when tracing around a shape can start to make a big difference, so try to match as close as you can, though, it can be helpful to have some of this extra space for "ease" so that the seam allowances you'll be adding later don't make the outfit too tight to put on.
When you like the shape of the main body of the garment, you can add sleeves if needed. Consider the body of the pony and whether it will be tough to dress. Outfits with sleeves will need a seam down the back, because ponies can't put their arms slightly backwards like we can. To get your pattern off it's totally ok to cut anywhere you need to, and tape it back together off the pony, and cut again where you want a seam to actually lay. 'Tis the magic of pattern drafting. Seams are completely movable!
I'll quit blabbing at this stage because I'm over-explaining again, but I'm always happy to try to explain more if anyone needs it!
this is seriously so helpful!! ^__^
