Pokéfind

Route 1: Pidgey, Ratatta, Budew, Pikachu, Kanto Starters (if you have the gamepass), Roaming Legendaries

Route 2: Pidgey, Rattata, Pikachu, Roaming Legendaries

Viridian Forest: Caterpie, Metapod, Weedle, Kakuna, Pikachu, Eevee (if you have the gamepass), Roaming Legendaries

Route 22: Nidoran♂, Nidoran♀, Mankey, Rattata, Heracross, Roaming Legendaries

Route 3: Pidgey, Mankey, Spearow, Ralts, Swablu, Roaming Legendaries

Mt. Moon: Zubat, Geodude, Larvitar (if you have the gamepass), Trapinch (if you have the gamepass), Aron (if you have the game pass), Aerodactyl, Clefairy, Kabuto, Paras, Cranidos, Omanyte, Swinub, Regirock, Roaming Legendaries

Route 4: Spearow, Sandshrew, Ekans, Magikarp, Roaming Legendaries

Route 5: Meowth, Bellsprout, Oddish, Drifloon, Mankey, Roaming Legendaries

Route 6: Oddish, Pidgey, Rattata, Slowpoke, Meowth, Psyduck, Magnemite, Roaming Legendaries

Route 11: Diglett, Slakoth, Sandshrew, Zangoose, Seviper, Snorlax, Dugtrio, Drowzee, Roaming Legendaries

Route 12: Poliwag, Krabby, Magikarp, Goldeen, Keldeo (champion badge required), Staryu, Roaming Legendaries

PokemonTower: Ghastly, Misdreavus, Giratina (champion badge required), Spiritomb (champion badge required), Cubone, Roaming Legendaries

Route 10: Magnemite, Voltorb, Onix, Machop, Nidoran♂, Nidoran♀, Murkrow, Shuppet, Zapdos, Roaming Legendaries

Route 7: Ekans, Pidgey, Sandshrew, Vulpix, Growlithe, Roaming Legendaries

Route 8: Rattata, Sandshrew, Growlithe, Venonat, Vulpix, Mankey, Ekans, Roaming Legendaries

Route 16: Rattata, Doduo, Spearow, Fearow, Tropius, Grimer, Roaming Legendaries

Fuchsia City: Scyther, Tauros, Dratini, Dragonair, Tangela, Kangaskhan, Farfetch'd, Exeggcute, Nidorina, Nidorino, Chansey, Rhyhorn, Skorupi, Roaming Legendaries

Route 19: Articuno, Tentacool, Psyduck, Goldeen, Seel, Horsea, Larvesta (when you have been in there for a while), Roaming Legendaries

Seafoam Cave: Lapras, Spheal, Seel, Snorunt, Zubat, Swinub, Sneasel, Bronzor, Kyreum (champion badge required), Roaming Legendaries

Route 17: Ponyta, Koffing, Venonat, Raticate, Roaming Legendaries

Route 21: Electabuzz, Koffing, Raticate, Pidgeotto, Hypno, Seel, Roaming Legendaries

Cinnabar Volcano: Ryhorn, Dugtrio, Magmar, Moltres (in the orange dirt/grass, there are two of them), Machoke, Sandslash, Graveler, Regice, Roaming Legendaries

Victory Road: Marowak, Machoke, Primeape, Starly (when you have been in there for a while.), Onix, Gible, Golbat, Graveler, Solrock, Lunatone, Lickitung, Dialga (champion badge required), Registeel, Roaming Legendaries

Mysterious Grotto: Pichu, Pidgey, Kadabra, Houndour, Gyrados, Electrike, Noctowl, Hoothoot, Wingull, Baltoy, Spoink, Torkoal, Remoraid, Mantine, Snorunt, Deoxys (if Solrock and Lunatone are in your party), Roaming Legendaries

Elegant Valley: Ponyta (in speed grass), Vulpix (in speed grass), Meowth (in speed grass), Lotad (in sp. defense grass), Drowzee (in sp. defense grass), Wooper (in hp grass), Chinchou (in hp grass), Togepi (in sp. defense grass), Hoppip (in sp. defense grass), Venonat (in sp. defense grass), Machoke (in attack grass), Absol (in attack grass), Piloswine, (in attack grass), Fraxure (in attack grass), Axew (in attack grass), Zweilous (in attack grass), Deino (in attack grass), Machop, (in attack grass), Swinub (in attack grass), Cubone (in ??? grass), Durant (in defense grass), Psyduck (in sp. attack grass), Golduck (in sp. attack grass), Roselia (in sp. attack grass), Ralts (in sp. attack grass), Kirlia (in sp. attack grass), Mr. Mime (in sp. defense grass), Gloom (in sp. attack grass), Oddish (in sp. attack grass), Larvesta (in sp. attack grass), Aipom (in speed grass), Palkia (champion badge required, in attack grass), Geodude (in defense grass), Sandshrew (in defense grass), Sandslash (in defense grass), Graveler (in defense grass), Onix (in defense grass), Roaming Legendaries