I wonder whether the Kzinti might be mentioned? There inclusion into Trek lore seems a tricky issue.
They and Earth were in conflict some "200 years" before 2269 (TAS: The Slaver Weapon
That would only happen with Larry Niven's blessing, and I'm not sure he'd be inclined to grant it, particularly since there's been a spate of new Known Space novels over the past few years co-written by Niven and Edward Lerner, the Fleet of Worlds
series, so it's a going concern again. I tend to feel that Trek and Known Space should remain their own distinct universes anyway.
Despite that preference, I have actually given some thought to whether TSW's backstory could somehow be tweaked in a way compatible with currently known Trek history, and I just couldn't see it. We know from "Terra Nova" that Earth's first interstellar colony was founded in 2078 and failed five years later, and we don't know how much later it was that Alpha Centauri, Vega, and other worlds were colonized. But it does seem that Earth expanded rather slowly in those early decades, and that the Vulcans were overseeing them rather closely, and probably protecting them from potential threats. The Earth we saw at the start of ENT was quite naive about interstellar contacts, probably because of Vulcan sheltering; Archer and his crew didn't know much about other races and didn't expect they'd run into many hostile aliens. If they'd been through a series of wars against a vicious race of spacegoing tigers in the previous century, they wouldn't have had such rosy expectations.