There are so many pieces of tack that can be used in ponyplay, and a staggering number of variations and designs of a given piece of tack. As a pony who keeps his human persona, I have a great affinity for all pieces of pony tack, and a person "forced" into ponyplay, I especially love using or adapting with as minimal modification as possible bio-equine tack and equipment. Anyway, I do have my favorites, and I list them here if you are interested:
#1 - Okay, so after saying all that about loving bio-equine tack, I have to contradict myself :) for my number one because I absolutely love my pony boots! My Reactor (formerly Kaysers) knee high hoof boots are definitely my favorite piece of pony equipment. While I can walk and jog in them, it is not easy to do so, which adds a degree of restriction (which I love) and forces me to put a bit of effort into keeping up when a trainer is leading me...an extra degree of submission I suppose. Also, I think the hoof part looks great.
#2 - My bit and bridle combination. The bit I really love is the one I use for intense training sessions and showing (for ordinary training sessions, or if I am going to be wearing the bit for more extended periods of time I typically have a standard rubber snaffle mouthpiece): a Pelham bit with a modified spoon/spade mouthpiece. The mouthpiece is angled upwards such that the spoon part of the bit naturally sits at around a 45° angle to the tongue. The spoon part of the bit has its concave end facing downwards with the tongue itself fitting inside. My tongue is pierced facilitating direct attachment of my tongue to spoon part of the bit. This keeps the spoon portion covering and almost touching my tongue which discourages me from playing with the bit. There are rubber spikes on both sides of the spoon so when the curb rein is applied, the bit will rotate upwards bringing the spikes in contact with the roof of my mouth. This is actually pretty uncomfortable especially with my tongue forced to go along with the bit.
Note: let me give credit here to Jurgen von Stuka & his © 1999 story "SUMMER SCHOOL" for inspiration. The bit I made (via modification of a bio-equine spoon/spade bit), including its point of attachment to my tongue piercing, is based on the "correction bit" worn by the girl as part of a double bridle. Also, I am working on an illustrated tutoral to show you how to make a similar bit for you/your pony out of a simple curb bit and a spoon to avoid having to pay for an expensive spoon/spade show bit.