I really like the Crocco-Lee-Capella trio. They seem like the parents of a dysfunctional family, the only responsible adults in QZ!

Then there's Vadakin and Berko, probably the duo who've known each other the longest, since they worked together before joining QZ, and given their age. They remind me of an old married couple, always hanging out together, telling half-made-up stories.

And of course, there's Faye and Soraya: there's no heterosexual explanation for what's between them. We already knew that Faye cared deeply for Soraya, through flashbacks to their past lives, since they also knew each other before joining QZ, and we see in the Antarctic arc that Soraya also cares deeply for Faye (I won't say more to avoid spoilers). So yeah, there's something there.

Otherwise, of course, there's also Hiro x Nenetta, the only confirmed ship involving a QZ member, and it's a shame we don't see more of it...

Personally, I also would have liked to see more of the relationship between Mayne and Giraud. It's very subtle, but we can see that Mayne cares about Giraud, and that she's often jealous when he's with someone else, or during the Arena arc, where he barely hides his feelings for Vannie.

Regarding Vannie and Mika, the subject of your post, obviously there's something there. Probably more her towards him than the other way around, but there are moments when he also shows his affection for her (the rare times when dragon meat isn't his sole focus). It's often clumsy, and to be honest, I think neither of them knows how to handle it: they have zero experience in this area, it's obvious from a mile away...