Although the Ritos are supposed to be descendants of the Zora and both exist in BotW...so yeah :>.
And the ghouls of Fallout were supposed to only exist from a single vault in California, and were explicitly said to be the first and last of their kind... but then, they were popular, and the game got sequels, so, enh, any time anyone gets hit with enough radiation, they'll randomly turn into a ghoul or a supermutant, whatever's more convenient for marketing.