A majority of my OCs are single, which means that they can be paired up with anyone really, but some have canonically dated others in the past. Here's some examples of characters of mine who are dating:
-Marten and Futo are dating, despite being long-distance partners
-Despite being frenemies, Sagong and Glitch are gay, but they don't show it to each other
-Oyster has canonically dated and had a relationship with a Lucario named Inu
-Futo himself used to be partners with Momoka, at some points even being a co-star for her adult movies