| # | Pokémon | Element | Location |
| A | |||
| 63 | Abra | Psychic | Route 24, 25 |
| 142 | Aerodactyl | Rock/Flying | Cinnabar Island (Give man in lab the Old Amber) |
| 65 | Alakazam | Psychic | Evolves from Kadabra by trade |
| 24 | Arbok | Poison | Evolves from Ekans at Lv22, Cinnabar Island |
| 59 | Arcanine | Fire | Evolves from Growlithe with use of a Fire Stone |
| 168 | Ariados | Bug/Poison | Evolves from Spinarak at Lv22 |
| 144 | Articuno | Ice/Flying | Seafoam Islands |
| 184 | Azumarill | Water | Evolves from Marill at Lv18 |
| 298 | Azurill | Water | Breed from two Marill or Azumarill |
| B | |||
| 15 | Beedrill | Bug/Poison | Evolves from Kakuna at Lv10 |
| 182 | Bellossom | Grass | Evolves from Gloom with the use of a Sun Stone |
| 69 | Bellsprout | Grass/Poison | Route 5, 24, 25, Two, Three and Six Island |
| 9 | Blastoise | Water | Evolves from Wartortle at Lv36 |
| 242 | Blissey | Normal | Evolves from Chansey when happy |
| 1 | Bulbasaur | Grass/Poison | Starting Pokémon |
| 12 | Butterfree | Bug/Flying | Evolves from Metapod at Lv10 |
| C | |||
| 10 | Caterpie | Bug | Viridian Forest, Six Island |
| 251 | Celebi | Grass/Psychic | Nintendo Download Events, Gameshark |
| 113 | Chansey | Normal | Safari Zone |
| 6 | Charizard | Fire/Flying | Evolves from Charmeleon at Lv36 |
| 4 | Charmander | Fire | Starting Pokémon |
| 5 | Charmeleon | Fire | Evolves from Charmander at Lv16 |
| 36 | Clefable | Normal | Evolves from Clefairy with use of a Moon Stone |
| 35 | Clefairy | Normal | Mt. Moon, Game Corner |
| 173 | Cleffa | Normal | Breed from two Clefairy or Clefable |
| 91 | Cloyster | Water/Ice | Evolves from Shellder with use of a Water Stone |
| 169 | Crobat | Poison/Flying | Evolves from Golbat when happy |
| 104 | Cubone | Ground | Pokémon Tower, Seven Island |
| D | |||
| 225 | Delibird | Ice/Flying | Four Island |
| 386 | Deoxys | Psychic | Nine Island (only reachable with a special Nintendo Ticket) |
| 87 | Dewgong | Water/Ice | Evolves from Seel at Lv34, Seafoam Islands, Four Island |
| 50 | Diglett | Ground | Diglett's Cave |
| 132 | Ditto | Normal | Route 13 |
| 85 | Dodrio | Normal/Flying | Evolves from Doduo at Lv31, Safari Zone |
| 84 | Doduo | Normal/Flying | Safari Zone, Route 16, 17, 18 |
| 232 | Donphan | Ground | Evolves from Phanpy at Lv25 |
| 148 | Dragonair | Dragon | Evolves from Dratini at Lv30 |
| 149 | Dragonite | Dragon | Evolves from Dragonair at Lv55 |
| 147 | Dratini | Dragon | Celadon City Gamecorner, Safari Zone |
| 96 | Drowzee | Psychic | Route 11, Three Island |
| 51 | Dugtrio | Ground | Evolves from Diglett at Lv26, Diglett's Cave |
| 206 | Dunsparce | Normal | Three Island |
| E | |||
| 133 | Eevee | Normal | Cerladon City in the Celadon Villa |
| 23 | Ekans | Poison | Route 4, 8, 9, 10, 11 |
| 125 | Electabuzz | Electric | Power Plant |
| 101 | Electrode | Electric | Evolves from Voltorb at Lv30, Secret Dungeon, Cinnabar Island (trade for Raichu) |
| 239 | Elekid | Electric | Breed from two Electabuzz |
| 244 | Entei | Fire | Found randomly in tall grass in Kanto (only if Bulbasaur was chosen as the starting Pokémon) |
| 196 | Espeon | Psychic | Evolves from Eevee when happy, by day (evolution only possible in R/S) |
| 102 | Exeggcute | Grass/Psychic | Safari Zone |
| 103 | Exeggutor | Grass/Psychic | Evolves from Exeggcute with use of a Leaf Stone |
| F | |||
| 83 | Farfetche'd | Normal/Flying | Vermillion (Trade) |
| 22 | Fearow | Normal/Flying | Evolves from Fearow at Lv20, Route 16, 17, 18, One, Two, Six and Seven Island |
| 136 | Flareon | Fire | Evolves from Eevee with use of a Fire Stone |
| 162 | Furret | Normal | Evolves from Sentret at Lv15 |
| G | |||
| 92 | Gastly | Ghost/Poison | Pokémon Tower, Five Island |
| 94 | Gengar | Ghost/Poison | Evolves from Haunter when traded |
| 74 | Geodude | Rock/Ground | Mt. Moon, Rock Tunnel, Victory Road, One Island |
| 44 | Gloom | Grass/Poison | Evolves from Oddish at Lv21, Route 12, 13, Two, Three and Six Island |
| 42 | Golbat | Poison/Flying | Evolves from Zubat at Lv22, Seefoam Islands, Victory Road, Four and Five Island |
| 118 | Goldeen | Water | Route 6, 22, 23, 25, Secret Dungeon, Fuchsia City, Viridian City, Safari Zone, Two, Three, Four, Six Island |
| 55 | Golduck | Water | Evolves from Psyduck at Lv33, One, Two and Three Island, Leaf Green: Seafoam Islands |
| 76 | Golem | Rock/Ground | Evolves from Geodude when traded |
| 75 | Graveler | Rock/Ground | Evolves from Geodude at Lv25, Victory Road, One Island |
| 88 | Grimer | Poison | Cinnabar Island |
| 58 | Growlithe | Fire | Cinnabar Island, Route 8 |
| 130 | Gyarados | Water/Flying | Evolves from Magikarp at Lv20, almost anywhere (fishing) |
| H | |||
| 93 | Haunter | Ghost/Poison | Evolves from Gastly at Lv25, Pokémon Tower, Five Island |
| 214 | Heracross | Bug/Fighting | Six Island |
| 107 | Hitmonchan | Fighting | Saffron City Dojo |
| 106 | Hitmonlee | Fighting | Saffron City Dojo |
| 237 | Hitmontop | Fighting | Evolves from Tyrogue at Lv20 if its attack is the same as its defence |
| 250 | Ho-oh | Fire/Flying | Eight Island (only reachable with a special Nintendo Ticket) |
| 187 | Hoppip | Grass/Flying | Five Island |
| 116 | Horsea | Water | Cinnabar Island, Seafoam Islands, Cerulean City, Vermillion City, Route 10, 12, 19, 20, 21, 24, One, Three, Four, Five, Six, Seven Island |
| 97 | Hypno | Psychic | Evolves from Drowzee at Lv26, Three Island |
| I | |||
| 174 | Igglybuff | Normal | Breed from two Jigglypuff or Wigglytuff |
| 2 | Ivysaur | Grass/Poison | Evolves from Bulbasaur at Lv16 |
| J | |||
| 39 | Jigglypuff | Normal | Route 3 |
| 135 | Jolteon | Electric | Evolves from Eevee with use of a Thunder Stone |
| 189 | Jumpluff | Grass/Flying | Evolves from Skiploom at Lv27 |
| 124 | Jynx | Ice/Psychic | Celadon City (Trade for Poliwhirl) |
| K | |||
| 140 | Kabuto | Rock/Water | Cinnabar Island (Give man in lab the Dome Fossil) |
| 141 | Kabutops | Rock/Water | Evolves from Kabuto at Lv40 |
| 64 | Kadabra | Psychic | Evolves from Abra at Lv16, Game Corner |
| 14 | Kakuna | Bug/Poison | Evolves from Weedle at Lv7, Route 24, 25, Six Island |
| 115 | Kangaskhan | Normal | Safari Zone |
| 230 | Kingdra | Water/Dragon | Evolves from Seadra when traded and holding a Dragon Scale |
| 99 | Kingler | Water | Evolves from Krabby at Lv28, Seafoamislands, Secret Dungeon, Route 23, Five Island |
| 109 | Koffing | Poison | Cinnabar Island, Celadon City |
| 98 | Krabby | Water | Route 4, 6, 11, 12, 13, 17, 18, 24, 25, Cerulean City, Vermillion City, Safari Zone, Fuchsia City, Three, Five Island |
| L | |||
| 131 | Lapras | Water/Ice | Saffron City Silph Co. Building, Icefall Cave on Four Island |
| 246 | Larvitar | Rock/Ground | Seven Island in the Sevault Canyon |
| 166 | Ledian | Bug/Flying | Evolves from Ledyba at Lv18 |
| 165 | Ledyba | Bug/Flying | Six Island |
| 108 | Lickitung | Normal | Route 18 |
| 249 | Lugia | Psychic/Flying | Eight Island (only reachable with a special Nintendo Ticket) |
| M | |||
| 68 | Machamp | Fighting | Evolves from Machoke when traded |
| 67 | Machoke | Fighting | Evolves from Machop at Lv28, Victory Road, One Island |
| 66 | Machop | Fighting | Rock Tunnel, Victory Road, One Island |
| 240 | Magby | Fire | Breed from two Magmar |
| 219 | Magcargo | Fire/Rock | Evolves from Slugma at Lv38 |
| 129 | Magikarp | Water | Fish anywhere with an Old Rod |
| 126 | Magmar | Fire | Cinnabar Island, One Island |
| 81 | Magnemite | Electric/Steel | Power Plant |
| 82 | Magenton | Electric/Steel | Evolves from Magnemite at Lv30, Power Plant |
| 56 | Mankey | Fighting | Route 5, 8 |
| 226 | Mantine | Water/Flying | Seven Island |
| 183 | Marill | Water | Evolves form Azurill when happy |
| 105 | Marowak | Ground | Evolves from Cubone at Lv28, Victory Road, Seven Island |
| 52 | Meowth | Normal | Route 5, 8, Three, Five, Six and Seven Island |
| 11 | Metapod | Bug | Evolves from Caterpie at Lv7, Viridian Forest, Route 24, 25, Six Island |
| 151 | Mew | Psychic | Only available in Pokémon Emerald |
| 150 | Mewtwo | Psychic | Secret Dungeon |
| 200 | Misdreavus | Ghost | Five Island |
| 146 | Moltres | Fire | One Island |
| 122 | Mr Mime | Psychic | Route 2 (trade for Abra) |
| 89 | Muk | Poison | Evolves from Grimer at Lv38, Cinnabar Island |
| 198 | Murkrow | Dark/Flying | Five Island |
| N | |||
| 177 | Natu | Psychic/Flying | Six Island |
| 34 | Nidoking | Poison/Ground | Evolves from Nidorino with use of a Moon Stone |
| 31 | Nidoqueen | Poison/Ground | Evolves from Nidorina with use of a Moon Stone |
| 29 | Nidoran(f) | Poison | Safari Zone, Route 22 |
| 32 | Nidoran(m) | Poison | Safari Zone, Route 22 |
| 30 | Nidorina | Poison | Evolves from Nidoran(f) at Lv16, Safari Zone, Fire Red: Game Corner |
| 33 | Nidorino | Poison | Evolves from Nidoran(m) at Lv16, Safari Zone, Leaf Green: Game Corner |
| 38 | Ninetales | Fire | Evolves from Vulpix with use of a Fire Stone |
| O | |||
| 224 | Octillery | Water | Evolves from Remoraid at Lv25 |
| 43 | Oddish | Grass/Poison | Route 5, 12, 13, 24, 25, Two, Three and Six Island |
| 138 | Omanyte | Rock/Water | Cinnabar Island (Give man in lab the Helix Fossil) |
| 139 | Omastar | Rock/Water | Evolves from Omanyte at Lv40 |
| 95 | Onix | Rock/Ground | Rock Tunnel, Victory Road, Seven Island |
| P | |||
| 46 | Paras | Bug/Grass | Mt. Moon, Safari Zone |
| 47 | Parasect | Bug/Grass | Evolves from Paras at Lv24, Safari Zone |
| 53 | Persian | Normal | Evolves from Meowth at Lv28, One, Two, Three, Five, Six and Seven Island |
| 231 | Phanpy | Ground | Seven Island |
| 172 | Pichu | Electric | Breed from two Pikachu or Raichu |
| 18 | Pidgeot | Normal/Flying | Evolves from Pidgeotto at Lv36 |
| 17 | Pidgeotto | Normal/Flying | Evolves from Pidgey at Lv18, Route 21, Three Island, Five Island |
| 16 | Pidgey | Normal/Flying | Route 1, 2, 3, 5, 8, 12, 13, 21, 25, Three Island, Five Island |
| 25 | Pikachu | Electric | Viridian Forest, Power Plant |
| 221 | Piloswine | Ice/Ground | Evolves from Swinub at Lv38 |
| 127 | Pinsir | Bug | Safari Zone |
| 186 | Politoed | Water | Evolves from Poliwhirl when traded holding a King Stone |
| 60 | Poliwag | Water | Pallet Town, Viridian City, Route 22, Four and Six Island (Fishing) |
| 61 | Poliwhirl | Water | Evolves from Poliwag at Lv25, Celadon City, Route 10, Two, Four and Six Island |
| 62 | Poliwrath | Water/Fighting | Evolves from Poliwhirl with use of a Water Stone, Two Island |
| 77 | Ponyta | Fire | Cinnabar Island, One Island |
| 137 | Porygon | Normal | Celadon City Game Corner for 9999 coins |
| 233 | Porygon 2 | Normal | Evolves from Porygon when traded holding the item Upgrade |
| 57 | Primeape | Fighting | Evolves from Mankey at Lv28, Route 9, 42 |
| 54 | Psyduck | Water | Route 4, 24, 25, Cerulean City, Safari Zone, One, Two, Three, Four, Five, Six and Seven Island |
| 247 | Pupitar | Rock/Ground | Evolves from Larvitar at Lv30 |
| Q | |||
| 195 | Quagsire | Water/Ground | Evolves from Wooper at Lv20 |
| 211 | Quilfish | Water/Poison | Five, Six and Seven Island |
| R | |||
| 26 | Raichu | Electric | Evolves from Pikachu with use of a Thunder Stone, Power Plant |
| 243 | Raikou | Electric | Found randomly in tall grass in Kanto (only if Squirtle was chosen as the starting Pokémon) |
| 78 | Rapidash | Fire | Evolves fropm Ponyta at Lv40, One Island |
| 20 | Raticate | Normal | Evolves from Rattata at Lv20, Route 16, 17, 18, 21 |
| 19 | Rattata | Normal | Route 1, 2, 4, 9, 10, 16, 17, 18, 21,22 |
| 223 | Remoraid | Water | Five, Six and Seven Island |
| 112 | Rhydon | Rock/Ground | Evolves from Rhyhorn at Lv42 |
| 111 | Rhyhorn | Rock/Ground | Safari Zone |
| S | |||
| 26 | Sandshrew | Ground | Route 4, 11, 8 |
| 27 | Sandslash | Ground | Evolves from Sandshrew at Lv22 |
| 212 | Scizor | Bug/Steel | Evolves from Scyther when traded holding Metall Coat |
| 123 | Scyther | Bug/Flying | Safari Zone, Fire Red: Celadon City Game Corner |
| 117 | Seadra | Water | Evolves from Horsea at Lv32, Route 19, 20, 21, One, Three, Four, Five, Six, Seven |
| 119 | Seaking | Water | Evolves from Goldeen at Lv33, Safari Zone, Fuchsia City, Three Island |
| 86 | Seel | Water | Seafoam Islands, Four Island |
| 161 | Sentret | Normal | Five, Six and Seven Island |
| 90 | Shellder | Water | Pallet Town, Vermillion City, Cinnabar Island, One, Four and Five Island |
| 227 | Skarmory | Steel/Flying | Seven Island |
| 188 | Skiploom | Grass/Flying | Evolves from Jumpluff at Lv27 |
| 80 | Slowbro | Water/Psychic | Evolves from Slowpoke at Lv37, Route 23, Route 18 (Trade), Secret Dungeon, One and Two Island |
| 199 | Slowking | Water/Psychic | Evolves from Slowbro when traded holding a King Rock |
| 79 | Slowpoke | Water/Psychic | Seafoam Islands, Safari Zone, Celadon City, Route 10, One, Two, Four, Five, Six and Seven Island |
| 218 | Slugma | Fire | One Island |
| 238 | Smoochum | Ice/Psychic | Breed from a Jynx and a Ditto |
| 215 | Sneasel | Dark/Ice | Four Island |
| 143 | Snorlax | Normal | Route 12, 16 |
| 21 | Spearow | Normal | Route 3, 4, 11, 9, 10, 16, 17, 18, 22, One, Two, Six and Seven Island |
| 167 | Spinarak | Bug/Poison | Six Island |
| 7 | Squirtle | Water | Starting Pokémon |
| 121 | Starmie | Water | Evolves from Starmie with use of a Water Stone |
| 120 | Staryu | Water | Pallet Town, Vermillion City, Cinnabar Island, One, Four, Five Island |
| 208 | Steelix | Steel/Ground | Evolves from Onix when traded holding Metall Coat |
| 245 | Suicune | Water | Found randomly in tall grass in Kanto (only if Charmander was chosen as the starting Pokémon) |
| 220 | Swinub | Ice/Ground | Four Island |
| T | |||
| 114 | Tangela | Grass | Route 21, One Island |
| 128 | Tauros | Normal | Safari Zone |
| 72 | Tentacool | Water/Poison | Route 12, 13, 17, 18, 19, 20, 21, Pallet Town, Viridian City, One, Three, Five, Six and Seven Island |
| 73 | Tentacruel | Water/Poison | Evolves from Tentacool at Lv30, One, Six and Seven Island |
| 175 | Togepi | Normal | Hatches from the Egg from Five Island |
| 176 | Togetic | Normal | Evolves from Togepi when happy |
| 148 | Tyranitar | Rock/Dark | Evolves from Pupitar at Lv55 |
| 236 | Tyrogue | Fighting | Breed from two Hitmonlee, Hitmonchan or Hitmontop |
| U | |||
| 197 | Umbreon | Dark | Evolves from a happy Eevee at night (Evolution only possible in R/S) |
| 201 | Unown | Psychic | Seven Island |
| V | |||
| 134 | Vaporeon | Water | Evolves from Eevee with use of a Water Stone |
| 49 | Venomoth | Bug/Poison | Evolves from Venonat at Lv31, Safari Zone, Three Island |
| 48 | Venonat | Bug/Poison | Safari Zone, Victory Road, Three Island |
| 3 | Venusaur | Grass/Poison | Evolves from Ivysaur at Lv32 |
| 71 | Victreebell | Grass/Poison | Evolves from Weepinbell with use of a Leaf Stone, Route 12, 13 |
| 45 | Vileplume | Grass/Poison | Evolves from Gloom with use of a Leaf Stone |
| 100 | Voltorb | Electric | Route 9, 10, Power Plant |
| 37 | Vulpix | Fire | Route 8 |
| W | |||
| 8 | Wartortle | Water | Evolves from Squirtle at Lv16 |
| 13 | Weedle | Bug/Poison | Viridian Forest, Route 24, 25, Six Island |
| 70 | Weepinbell | Grass/Poison | Evolves from Bellsprout at Lv21, Route 12, 13, Two, Three and Six Island |
| 110 | Weezing | Poison | Evolves from Koffing at Lv35, Cinnabar |
| 40 | Wigglytuff | Normal | Evolves from Jigglypuff with use of a Moon Stone |
| 202 | Wobbuffet | Psychic | Six Island, Secret Dungeon |
| 194 | Wooper | Water/Ground | Four and Six Island |
| 360 | Wynaut | Psychic | Breed from two Wobbuffet |
| X | |||
| 178 | Xatu | Psychic/Flying | Evolves from Natu at Lv25 |
| Y | |||
| 193 | Yanma | Bug/Flying | Six Island |
| Z | |||
| 145 | Zapdos | Electric | Powerplant |
| 41 | Zubat | Poison/Flying | Mt. Moon, Rock Tunnel, Seafoam Islands, Victory Road, Four, Five and Six Island |