At the end of the Pokémon World Championships, it was revealed that a lot of starter Pokémon would be added to Pokémon Scarlet and Pokémon Violet, you can see them in the trailer below.

The returning Pokemon are currently confirmed to be Chespin, Scorbunny, Chimchar, Totodile, Squirtle, Tepig, Snivy, Rowlet, Treecko, Mudkip, and Fennekin.

Those trainers who have collected those critters in past games and have transferred them into Pokémon Home will be able transfer them into the game, once the update goes live.

While the trailer shows the starters in The Indigo Disk, there is no word on if they will be added before the second part of the DLC arrives.