Pokemon Tower Defense 1 Catch Pokemon

From Oak's Laboratory

Bulbasaur: Available from the start, evolves into Ivysaur at level 16 and Venusaur at level 32.
Charmander: Available from the start, evolves into Charmeleon at level 16 and Charizard at level 36.
Squirtle: Available from the start, evolves into Wartortle at level 16 and Blastoise at level 36.

Out in the Wild

Pidgey: Can be caught in Route 1, evolves into Pidgeotto at level 18 and Pidgeot at level 36.
Caterpie: can be caught in the Viridian Forest, turns into Metapod at level 7 then into Butterfree at level 10.
Weedle: can be caught in the Viridian Forest, turns into Kakuna at level 7, then to Beedrill at level 10.
Rattata: can be caught in Oak's Lab, turns into Raticate at level 20.
Spearow: can be caught in Route 3, turns into Fearow at level 20.
Ekans: can be caught in Mt. Moon 1, turns into Arbok at level 22.
Pikachu: can be caught in the Viridian Forest, turns into Raichu with a Thunder Stone
Sandshrew: can be caught in Mt. Moon 1, turns into Sandslash at level 22.
Nidoran F: can be caught in Route 3, turns into Nidorina at level 16 and into Nidoqueen with a Moon Stone.
Nidoran M: can be caught in Route 3, turns into Nidorino at level 16 and into Nidoking with a Moon Stone.
Clefairy: can be caught in Mt. Moon 1, turns into Clefable with a Moon Stone.
Vulpix: can be caught in Mt. Moon 2, turns into Ninetails with a Fire Stone.
Jigglypuff: can be caught in Route 3, turns into Wigglytuff with a Moon Stone.
Zubat: can be caught in Mt. Moon 1, turns into Golbat at level 22.
Oddish: can be caught in Mt. Moon 2, turns into Gloom at level 21 and into Vileplum with a Leaf Stone.
Paras: can be caught in Viridian Forest 2, turns into Parasect at level 24.
Venonat: can be caught in the Safari Zone, turns into Venomoth at level 31.
Diglett: can be caught in Diglett's Cave, turns into Dugtrio at level 26.
Meowth: can be caught in Route 5, turns into Persian at level 28.
Psyduck: can be caught in Cerulean Gym with the Super Rod, turns into Golduck at level 33.
Mankey: can be caught in Route 3, turns into Primate at level 28.
Growlithe: can be caught in Mt. Moon 2, turns into Arcanine with a Fire Stone.
Poliwag: can be caught in Mt. Moon 2, turns into Poliwhirl at level 25 and into Poliwrath with a Water Stone.
Abra: can be caught in Cerulean Gym, turns into Kadabra at level 16, and into Alakazam through trade.
Machop: can be caught in the Rock Tunnel, turns into Machoke at level 29, and into Machamp through trade.
Bellsprout: can be caught in Mt. Moon 2, turns into Weepinbell at level 21, and into Victreebell with a Leaf Stone.
Geodude: can be caught in Mt. Moon 1, turns into Graveler at level 25, and into Golem through trade.
Ponyta: can be caught in Cinnabar Island, turns into Rapidash at level 40.
Slowpoke: can be caught in the Safari Zone, turns into Slowbro at level 37.
Magnemite: can be earned as a Mystery Gift Pokemon, turns into Magneton at level 30.
Farfetch'd: can be earned as a trade reward for Spearow at Vermillion City, does not evolve.
Doduo: can be caught in the Safari Zone, turns into Dodrio at level 31.
Seel: can be earned as a Mystery Gift Pokemon, turns into Dewgong at level 34.
Grimer: can be caught in Cinnabar Island, turns into Muk at level 38.
Shellder: can be caught in Vermillion City with the Super Rod, turns into Cloyster with the Water Stone.
Gastly: can be caught in Poke Tower 1, turns into Haunter at level 25, and into Gengar through trade.
Onix: can be caught in Rock Tunnel, does not evolve.
Drowzee: can be caught in Diglett's Cave, turns into Hypno at level 26.
Krabby: can be caught in Cerulean Gym with Super Rod, turns into Kingler at level 28.
Voltorb: can be caught in Rock Tunnel, turns into Electrode at level 30.
Execute: can be caught in the Safari Zone, turns into Exegcutor with the Leaf Stone.
Cubone: can be caught in Poke Tower 1, turns into Marowak at level 28.
Hitmonlee and Hitmonchan: are awarded when you finish Saffron Dojo, but you may only choose one of the them (you can gain the other through trade).
Lickitung: can be earned as a Mystery Gift Pokemon, it does not evolve.
Koffing: can be caught in Cinnabar Island, turns into Weezing at level 35.
Rhyhorn: can be caught in the Safari Zone, turns into Rhydon at level 42.
Chansey: can be caught in the Safari Zone, it does not evolve.
Tangela: can be caught in Pallet Town, it does not evolve.
Kangaskhan: can be caught in Safari Zone, it does not evolve.
Horsea: can be caught in Route 19, turns into Seadra at level 32.
Goldeen: can be caught in Route 12, turns into Seaking at level 33.
Staryu: can be caught in Route 19, turns into Starmie with the Water Stone.
Mr. Mime: can be obtained by trading an Abra at Route 2, it does not evolve.
Scyther: can be caught in the Safari Zone, it does not evolve.
Jynx: can be obtained by trading a Poliwhirl at Cerulean Gym, it does not evolve.
Magmar: can be caught in Cinnabar Island, it does not evolve.
Pinsir: can be caught in the Safari Zone, it does not evolve.
Tauros: can be caught in the Safari Zone, it does not evolve.
Magikarp: can be caught in Cerulean Gym with the Old Rod, turns into Gyarados at level 20.
Lapras: can be caught in Route 12, it does not evolve.
Ditto: can be caught in Route 15, it does not evolve.
Eevee: can be caught in Route 18, and it can evolve into three forms. Giving it a Water Stone will turn it into a Vaporeon, a Lightning Stone will turn it into a Jolteon, and a Fire Stone will turn it into a Flareon.
Porygon: can be purchased from the Game Corner, it does not evolve.
Omanyte: can be chosen at Cinnabar Island, turns into OMASTAR at level 40. Or players can choose Kabuto which turns into Kabutops at level 40.
Aerodactyl: is awarded as a prize for completing Cinnabar Island without losing a single candy.
Snorlax: can be caught in Poke Tower 2, it does not evolve.
Dratini: can be caught in the Safari Zone, turns into Dragonair at level 30 and into Dragonite at level 55.

Special Pokémon

Articuno: can only be obtained by beating Seafoam Island with a party of level 100 Ice Pokemon.
Zapdos: can only be obtained by beating the Power Plant with a party of level 100 Electric Type Pokemon.
Moltress: can only be obtained by beating Victory Road with a party of level 100 Fire Type Pokemon.
Mewtwo: cannot be caught.
Mew: can be earned as a Mystery Gift Pokemon, it does not evolve.
Raikou: can be adopted from the Pokemon Adoption Center, it does not evolve.
Entei: can be adopted from the Pokemon Adoption Center, it does not evolve.
Suicune: can be adopted from the Pokemon Adoption Center, it does not evolve.
Celebi: cannot be caught.
Kyogre: cannot be caught.
Groudon: cannot be caught
Victini: was originally available as a Mystery Gift Pokemon, it does not evolve.

Final Notes:

The three legendary birds, Articuno, Zapdos, and Moltres, will be your final targets as they require 18 level 100 Pokemon to defeat (6 level 100 Pokemon for fire, lightning and water types).

Raikou, Entei and Sucine are called the three legendary beasts (or legendary cats/legendary dogs). They were voted in by fans to be turned into being permanently available, but the chances of owning one are extremely low.

Lastly, obtaining a Victini is still possible even if it's no longer available as a Mystery Gift. But players will have to scour the trades for a good deal.

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