I agree with all said above. Perhaps some Spiny Eels? Wolf Fish, but they’re aggressive. Ropefish, Plecos, Hoplos, those are all somewhat ancient or primitive. Don’t get one unless you have a large tank, but Arapaima. Bony tongues. Tarpon, but same goes for Arapaima is some cases. Lampreys, but I’m not sure how you’d keep one, as most are illegal and some are seasonal species, like some killies. Ripsaws, Irwini, Rock Bacu, Raphael Catfish. Those are just a few that came to mind.