Kobayashi-san Chi No Maid Dragon... · 4:04am
This anime has all the hallmarks of something that would be a natural crossover with Pony.
1. It's a good-natured anime/manga with magical dragons of varying types, talents, and personalities.
2. The dragons can open interdimensional portals.
3. The main cast are interested in different universes and can change their shape to blend in and learn, despite sill having many humorous misunderstandings.
4. They are very powerful and belong to two castes Order and Chaos, and yet they are not utterly bound to behave as though brainwashed. They have their own free will.
Thus, they could enter Pony and feel like natural parts of the story and learn all about the pony world and the dragons therein. And Discord might play an interesting role himself, given his affinity for Chaos.