Seers: They are fucking masterminds on both a grand and small scale. They can be well together, but I get the feeling that Terezi is a bit too chaotic for Rose. Not that chaos is a bad thing, but Rose is like a straight line while Terezi is a fluctuating graph. She can be on Rose’s serious level at times, but you know there are moments where she also goes off the rails. So while I could see them be together, I prefer Rose/Kanaya. Someone to match them tit for tat or however the expression goes.
Knights: This will be the funniest thing to see. They are going to snark each other to oblivion. Because Karkat is always angry, aggressive, and hot, while Dave is chill, calm, and cool. Their insults and raps will be glorious to see and watch. I think it would have to be Spades for it to work? Or at least that is what Karkat will view it as. But damn that would be fun to watch.
Witches: I would sort of imagine them to be like two hufflepuffs together. Soft, sweet, will obviously kick ass when threatened, focused on their garden and animals. I don’t know if I personally ship it, I haven’t really any ships with Jade in mind, but I can see them be cute together.
Heirs: Oh God Why. I…don’t?? I don’t see….Any Way….they can work together. John is way too nice to just boss Equius around for his….kinks….and Equius is a bit too weird for John to think about dating. Plus, John stated that he isn’t into guys, and I would feel weird trying to ship him with a guy after that. Can they be friends, yes. John can be friends with anybody. But Definitely NOT Dating.