Been obsessed with the Super Sons since forever, and honestly? The 'best' ships really depend on what flavor you're craving. Damian Wayne/Jon Kent just hits different from their younger counterparts. Fics that really dig into their post-'Teen Titans' dynamic, where Damian's trying to be less of a little terror and Jon's grappling with his Kryptonian legacy, are my absolute jam. There's this one, 'Of Sun and Shadows,' that nails the tension of them being pulled between their fathers' worlds while building something uniquely theirs.
If you want something completely off the wall, though, Damian Wayne/Jon-El (Earth-3) from 'DCeased' or 'Injustice' universes is a wild ride. It's all about the angsty 'enemies to something more' vibe, with Jon having that corrupted edge. It's not for everyone, but when it's done right, the chemistry is electric in a messed-up way.
For pure, tooth-rotting fluff, you can't go wrong with the classic Super Sons as kids. DamiJon fics set during the 'Super Sons' comic run are just pure joy. They capture that perfect balance of bickering and unwavering loyalty. I keep going back to 'Pajama Day' on AO3 whenever I need a pick-me-up.