From Bulbapedia, the community-driven Pokémon encyclopedia.
This is a list of Pokémon by their catch rate. Pokémon with higher catch rates are easier to capture than Pokémon with lower catch rates.
In Pokémon Omega Ruby and Alpha Sapphire, the catch rates of Kyogre, Groudon, Dialga, Palkia, Reshiram, and Zekrom, the game mascots made obtainable in those games that did not already have a catch rate of 3, were changed to 3, while the catch rate of Rayquaza was raised from 3 to 45.
In Pokémon Ultra Sun and Ultra Moon, the catch rates of Buzzwole, Pheromosa, Xurkitree, Celesteela, Kartana, and Guzzlord, six of the Ultra Beasts previously available in Sun and Moon, were all changed from 25, 255, 30, 25, 255, and 15, respectively, to 45, while the catch rate of Necrozma was raised from 3 to 255.
In Pokémon: Let's Go, Pikachu! and Let's Go, Eevee!, the catch rate of Bulbasaur was raised from 45 to 120. The catch rates of Buzzwole, Pheromosa, Xurkitree, Celesteela, Kartana, Guzzlord, Poipole, and Naganadel were changed from 45 to 25, 255, 30, 25, 255, 15, 15, and 15, respectively.
Generation I held items
In Pokémon Yellow, four Pokémon will have different held items than their Red/Blue counterparts when traded to Generation II. The starter Pikachu's "catch rate" value is set to 163 (as opposed to 190), which causes it to hold a Light Ball when traded over. A wild Kadabra's catch rate value is set to 96 upon capture (as opposed to 100), which gives it a TwistedSpoon when traded over. A wild Dragonair's catch rate is 27 (as opposed to 45), which gives it a Protein when traded over. Finally, a wild Dragonite's catch rate is 9 (as opposed to 45), which gives it an Antidote when traded over. However, wild Dragonite cannot normally be encountered in Pokémon Yellow, and Dragonite that were evolved will not be holding an Antidote when transferred.
The gift Pokémon from Pokémon Stadium will have exclusive held items when traded to Generation II. If obtained in Round 1, they will hold the Normal Box; if obtained in Round 2, they will hold the Gorgeous Box.
List of Pokémon