I think it's Karlach for the good side, and Shadowheart for the evil to neutral side.
I emphasize with your complaint, though. Karlach isn't really everyone's type and it feels forced in good playthroughs. I'm hoping Larian has romance options with NPCs that aren't quite part of your party, but on your side nonetheless. With what I've heard, I'm expecting a solid number of them.
There are certainly strong hints in Early Access content that a relationship with Lakrissa is a possibility. I certainly hope so!
