Kanto - Ash gets Bulbasaur, Charmander, and Squirtle
Johto - Ash gets Chikorita, Cyndaquil, and Totodile
Hoenn - Ash gets Treecko, May gets Torchic, and Brock gets Mudkip
Sinnoh - Ash gets Turtwig and Chimchar, Dawn gets Piplup
Unova - Ash gets Snivy, Tepig, and Oshawott
Kalos - Clemont gets Chespin, Serena gets Fennekin, Ash gets Froakie
Alola - Ash gets Rowlet and Litten, Lana gets Popplio
Galar - Goh gets Grookey, Scorbunny, and Sobble
Some of these Pokémon had previous Trainers, such as Charmander, but they ended up in the hands of the listed Trainers.
I hope this is what you were looking for.
Source: Experience and Bulbapedia