If this happened to Skyrim, it can happen to that game or Xenoverse 2. Most likely 2.
I don't mean fan-made races...I'm a die hard Dragon Ball fan and I know that there's a plethora of other named races within that universe, both in the canon and non canon of the anime. Yardrat, Brench, Kanassans, Kuhn, Hera, Saute, etc are all examples of extra species that could be added by mod experts.
I imagine it is possible to pull it off. Like, with the Yardrat option you can do more effective versions of Instant Transmission and be faster moving, Hera species you get Bojack's ultimate form, etc. There could be perks for each of the other races however many are added.