For me I start out in Kanto & Pikachu as my Starter Pokémon.
Kanto & Orange Islands: Pikachu, Pidgeot, Primeape, Venusaur, Charizard, Blastoise, Kingler, Weepinbell, Magneton, Cubone, Gengar, Hypno, Tauros, Muk, Omastar, Lapras, Snorlax, Hitmonlee, Rhydon, Tangela, Lickitung
Johto: Noctowl, Ariados, Meganium, Typhlosion, Feraligatr, Togetic, Heracross, Aipom, Ursaring, Donphan, Sunflora, Scizor, Murkrow, Hourdoom, Kingdra, Elekid(Shiny), Gilgar, Midreavus, Sneasel, Tyranitar, Dragonite
Hoenn: Swellow, Sceptile, Blaziken, Swampert, Aggron, Crawdaunt, Sableye, Kecleon, Torkoal, Duskclops, Medicham, Flygon, Relicanth, Glalie
Sinnoh: Staraptor, Luxray, Roserade, Empoleon, Torterra, Infernape, Toxicroak, Gastrodon(West), Mothim, Drapion, Ambipom(evolve from Aipom) Blissey, Spiritomb, Tangrowth( evolve from Tangela), Mismagius(evolve from Midreavus), Dusknoir( evolve from Duskclops), Gliscor( evolve from Gilgar), Bronzong, Lickilcky( evolve from Lickitung) Rampardos, Rotom, Magnezone.( evolve from Magneton), Lucario, Honchkrow( evolve from Murkrow) Weavile(evolve from Sneasel ), Garchomp, Electivire( Shiny & evolve from Elekid)
Unova: Unfezant(female), Krookodite, Serperior, Emboar, Samurott, Volcarona, Scrafty, Galvantula, Eelektrik, Reuniclus, Gigalith, Garbodor, Durant, Zoroark, Jellicent(female), Archeops, Beartic, Cofagrigus, Maractus, Bisharp, Bouffalant, Lampent, Golurk, Hydreigon, Haxorus
Kalos: Talonflame, Chesnaught, Delphox, Greninja, Talonflame, Florges, Heliolisk, Hawlucha Clawitzer, Tyrantrum, Pangoro, Meowstic(female), Aegislash, Klefki, Avalugg, Noivern
Alola: Toucannon, Vikiavolt, Lycanroc(Dusk Form), Primerina, Decidueye, Incineroar, Shiinotic, Golem(Alolan From) Mimikyu, Magmortar(Shiny), Crabominable, Oranguru, Golisopod, Marowak(Alolan Form & evolve from Cubone), Sandslash(Alolan Form), Drampa, Aerodactyl, Komm-o, Melmetal, Naganadel, Type: Null
Galar: Corviknight, Orbeetle, Cinderace, Inteleon, Rillaboom Boltund, Drednaw, Thievul, Coalossal, Slowking(Galar Form), Grapploct, Darmanitan(Galar Form), Toxtricity(Amped), Sirfetch'd, Polteageist, Grimmsnarl, Sandaconda, Centiskorch, Copperajah Dracovish, Arctovolt, Frosmoth, Hatterene, Runerigus, Alcremie, Perrserker, Eevee, Duraludon, Urshifu, Dragapult,
Hisui: Typhlosion(Hisuian Form), Decidueye(Hisuian Form), Samurott(Hisuian Form), Wydeer, Kleavor, Lilligant(Hisuian Form), Braviary( Hisuian Form), Zoroark (Hisuian Form), Overqwil, Electrode (Hisuias Form), Basculegon, Ursaluna(evolve from Ursaring) Arcanine(Hisuias Form), Sneasler, Avalugg(Hisuian Form), Goodra(Hisuian Form),