Finally I have designed myself a ponysona! They can be drawn as a FiM style or an oldschool style pony, I just happened to use an FiM template (see the image for credits).
Their name is Unlock, and its cutie mark is a gold-and-brown skeleton key with a heart-shaped flourish over a black-and-white spiral. Their hair is all the colors of their cutie mark, with blue eyes and white fur. They're a unicorn andtheir special talent is hypnotizing/brainwashing other ponies. >:D
And yes, Unlock is agender and has no genitalia. I debated making them female just with a flat chest in anthro form, but honestly, with all the magic and weird stuff that goes on in Equestria, I really don't see why you couldn't have a trans or nonbinary pony!