I'm not spoiling the name here, but I already did in the notes of one of my drawings.
Wild Pokemon found in this place:
B1: Arcanine, Gyarados, Lapras, Snorlax, Articuno (only one), Zapdos (only one), Moltres (only one), Dragonite, Mewtwo (only one), Mew (only one)
B2: Arcanine, Gyarados, Lapras, Snorlax, Dragonite, Crobat, Kingdra, Blissey, Raikou (only one), Entei (only one), Suicune (only one), Tyranitar, Lugia (only one), Ho-Oh (only one), Celebi (only one)
B3: Arcanine, Gyaraods, Lapras, Snorlax, Dragonite, Crobat, Kingdra, Blissey, Tyranitar, Swampert, Slaking, Milotic, Salamence, Metagross, Regirock (only one), Regice (only one), Registeel (only one), Latias (only one), Latios (only one), Kyogre (only one), Groudon (only one), Rayquaza (only one), Jirachi (only one), Deoxys (only one)
B4: Arcanine, Gyarados, Lapras, Snorlax, Dragonite, Crobat, Kingdra, Blissey, Tyranitar, Swampert, Slaking, Milotic, Salamence, Metagross, Garchomp, Magnezone, Rhyperior, Tangrowth, Electivire, Magmortar, Togekiss, Porygon-Z, Uxie (only one), Mesprit (only one), Azelf (only one), Dialga (only one), Palkia (only one), Heatran (only one), Regigigas (only one), Giratina (only one), Cresselia (only one), Manaphy (only one), Darkrai (only one), Shaymin (only one), Arceus (only one)
B5: Arcanine, Gyarados, Lapras, Snorlax, Dragonite, Crobat, Kingdra, Blissey, Tyranitar, Swampert, Slaking, Milotic, Salamence, Metagross, Garchomp, Magnezone, Rhyperior, Tangrowth, Electvire, Magmortar, Togekiss, Porygon-Z, Victini (only one), Darmanitan, Archeops, Vanilluxe, Haxorus, Hydreigon, Volcarona, Cobalion (only one), Terrakion (only one), Virizion (only one), Tornadus (only one), Thundurus (only one), Reshiram (only one), Zekrom (only one), Landorus (only one), Kyurem (only one), Keldeo (only one), Meloetta (only one), Genesect (only one)
You can probably guess what it is by now.