And then there was Reyes.
The Andromeda romance option I probably end up thinking about the most. It's the most fascinating in some specific tropey ways. While leaving a lot of room to build and explore more, about both the character and Ryder's relationship to him.
I desperately wish we got a sequel to Andromeda, to explore whatever these two got up to together.
But for what we got, there's so many angles through which you can look at this couple, and I think ultimately that's why he tends to heavily feature in a lot of fanfic and fanart:
The appeal of the dangerous but quippy bad boy, of course. Always a fan favorite.
There's a sort of opposites-attract vibe, if you play Ryder as good-hearted, wide-eyed, and comparatively not great at underworld maneuvering. Or at flirting.
There's the future potential of an almost scary power couple in there.
There's the potential, because Reyes' character is a little open-ended, of having crossed paths, maybe even having met before back in the Milky Way.
And it is one of the only Bioware romances that can end good... or like, really bad. And that's fun in and of itself, because now you've got the potential for the divorced trope to apply, too. (Which is one of my favorites. I'm so mad that there's no sequel where Ryder and Reyes can be divorced... resentfully... with space guns...)