GBA Pokémon hacks are fan-made hacks of official Pokémon games that were also sold on bootleg cartridges (presumably without the knowledge of the creators).
A hack of Ruby which replaces all Pokémon with original ones and takes place in Corna, a heavily-edited Hoenn. The game has a great number of spelling and grammatical errors, which result from the hack being translated from Spanish, and also contains profanity and adult themes.
While the best-known bootleg cartridge as played on the actual GBA contains serious glitches and errors, the current patch file release works well with VBA when the patch is applied to a clean Ruby ROM. The bootleg version has Gyarados on the boxart, stolen from the Pokémon Trading Card Game expansion "EX Holon Phantoms".
A Spanish hack and bootleg of Ruby in which the player plays as either Ash or Misty and travels around the Orange Archipelago (Naranja is a Spanish word which means "Orange"). Celebi appears on the box art and title screen.
A hack of FireRed. The game contains many new Pokémon, and glitch ones (such as MissingNo).
The description on the back of some bootleg boxes contains typos or poor English and punctuation, as is common with bootleg games. The front cover features a black recolored Chaos from the Sonic the Hedgehog franchise.
A hack of Ruby/Sapphire. Different versions exist, some with a lighter palette and some with text differences. The original ROM has a text box in the beginning of the game saying: "This game has been hacked by: The Phantom of Poké4Yu Inc." but this was removed from most cartridge versions. The cartridge versions also have the light palette.
A possible publisher could have the initials "VC" due to some of the cartridges having a sticker over the screw with the letters VC.
A hack of Pokémon Ruby (or Sapphire) for the Game Boy Advance. This hack was probably made by an unknown Spanish, American or Italian developer (according to the title or to the ESRB rating) named EMU LG. Despite the game is dated 2005 (see title screen pic), it was probably made after 2007, considering that the game has many elements from Pokémon Diamond and Pearl.