Probably still not found yet, well we have to wait for more.
I was being sarcastic here, Rappa, even though she became my favorite from the whole game, is not so popular unlike others, and as you can also see, people don't ship her with anyone because she only interacted with the trailblazer, which apparently is not something they want nor care. There might be one or two out there who did that but as you can see and even when searching for fanart of Rappa, you'll barely find anything that's not a normal one, lewds or a few with the trailblazer.
