Pitching the idea for "regional" Saiyans. Saiyans who evolve and adapt to their settled climates. Whis tells Goku and Vegeta that there are smaller Saiyan tribes that inhabit other less universes (not just U6). -

These Saiyans inhabit a water-based planet. They're based off of Japanese macaques or "hot spring monkeys". They're super lazy but can inflict heavy damage if you engage a fight with them.

They only really turn into Oozarus if you agitate them or they can't get access into the hot springs. Their skin and fur is thick enough to take the boiling temps of the spring but can scald regular skin. The spring has senzu-bean and muscle stimulator properties.

They don't really speak a lot since they sleep most of the time so they use ASL to communicate most of the time.

Powerwise I'd place them at SSJ3 level only when they're active fighting. They're fight primal style at ground-base. They cannot fly but can launch themselves in momentum. They can't sense energy but go by scent.

I'm really just entertaining the idea of "what if the Saiyans that didn't get boomed by Frieza off planet adapted and evolved" [The DBZ Turles Theory] or "Besides U6, what if we had actual Saiyan monke variations". [The DBS Multiverse Theory]
It's all in good fun.