Slammed! is my favourite of the official choice games. It definitely seems like an odd choice but it has one of my favourite choice game romances in it. I don’t even like wrestling so it’s a sign of how great the author’s writing is that I loved Slammed!
Choice of Deathless is another favourite of mine. I liked one of the romances in it but did feel it could have been more well developed. The plot was great though, as was the setting, actually the whole concept is one I really enjoyed and I liked the degree of choice.
Paradox Factor could definitely be read as a sci-fi romance since love is one of the primary motivations. I wouldn’t say the story is a romance as such since it tackles everything so quickly in broad sweeping strokes.
I liked one romance in Choice of Broadsides, but I didn’t think it was wrapped up well enough. It was clear it was added in after the fact.
The ones in Choice of the Vampire (have only played the first game) were too depressing for me. Although Vampire is good.
Heroes Rise is rather polarising. Some people love the relationships in it, others not so much. I enjoyed the game.
And everything else everyone has said here. I’ve likely forgotten many.