In official contexts, the group is referred to descriptively in several ways, including "Hoenn first partner Pokémon"[2], "first partner Pokémon of the Hoenn region"[1], and more.
This article is incomplete. Please feel free to edit this article to add missing information and complete it. Reason: Rival's Shroomish, Numel, Wailmer, Ludicolo, Slugma, Pelipper, Breloom, Magcargo and Wailord
In The Indigo Disk DLC, the Hoenn first partners can be caught in the wild at the Terarium. They are unlocked after upgrading the biomes through the League Club Room.
In the Ash & Pikachu manga, Professor Birch gives a Torchic to May.
Pokémon Adventures
In Pokémon Adventures, Professor Birch gifts a Torchic to Sapphire and a Mudkip to Ruby. Professor Birch was also revealed to be in possession of a Treecko, however the Pokéball containing the Pokémon was washed away in a flood. It was later found by Wally, and eventually came to be under the ownership of Emerald.
Pokémon Pocket Monsters
In Pokémon Pocket Monsters, Professor Birch is in possession of the three Hoenn first partner Pokémon to which he gifts to new Trainers. The only one he is seen giving out though is a Torchic which he gives to Sapphire.