Multiple partners? Okay, I'ma need a Gatomon and a BlackGatomon. Oh, OC not self. Hmmmm. You said tamer so the card swipey season. Don't think Aradain would do the best with that one, since there is strategy involved in the card use, usually. Plus I can't think of a specific digimon I'd like to pair her with. None of the water ones seem suitable. Maybe, Meicoomon? Cause holy beast that goes, very wrong, suits her, kinda. And if we skip the cards stuff and go for a Raguelmon or Rasielmon Biomerge, she should be able to handle the fighting that way.
Anima would be pretty good at that stuff, probably starting with a machine type digimon, Andromon line maybe? I wanna say Boltmon for the Biomerge, if you can even call it that, given Anima is an Automaton/Spirit. They are less of a direct fighter, so they might have a harder time at that point, but might manage.