Starters from Gen 7 return in Pokémon Scarlet & Violet's Indigo Disk DLC and appear in the wild as Pokémon for you to find and catch in nearly every new map area. The adorable Rowlet, Popplio, and Litten from Pokémon Sun & Moon's Alola Region are unlocked when you complete certain quests in the League Club. You may have to finish several smaller missions before you track down these familiar favorites.
How To Find (& Catch) Every Gen 7 Pokémon Starter (Scarlet & Violet Indigo Disk DLC)
Pokémon Scarlet & Violet's Indigo Disk DLC introduces a way to catch every starter from past Generations, including those from Gen 7's Sun & Moon.