In-Game Events:
* Mewtwo Event: You can encounter Mewtwo on Cinnabar Island after defeating the Elite Four and becoming champion. It is found in the Pokemon Mansion.
* Pikachu Event: At the beginning of the game, you can choose to start with either Bulbasaur, Charmander, or Squirtle. However, if you talk to the old man at the Viridian Forest, he will give you a Pikachu.
* Mew Event: This event is not available in the original FireRed game, but can be accessed through a glitch using the "MissingNo." glitch.
* Celebi Event: This event was available through a special promotional event in Japan, and can be accessed in the English version using a special event code.
Promotional Events:
* Mewtwo Event: A special event was held in Japan that allowed players to obtain a Mewtwo with special abilities.
* Jirachi Event: In Japan, there was an event where you could receive a Jirachi by downloading a special code.
* Deoxys Event: In Japan, there was an event where you could receive a Deoxys by downloading a special code.
* Other Promotional Events: Other promotional events were held in different countries, offering different Pokémon such as Darkrai, Shaymin, and Arceus.
Glitches:
* MissingNo. Glitch: This infamous glitch allows players to encounter a variety of rare Pokémon, including MissingNo. This glitch can also be used to obtain other Pokémon, including Mew.
* Other Glitches: There are other glitches that can be used to obtain rare Pokémon, but these are often complex and require a lot of technical knowledge.
Note: Most of the events mentioned above are unavailable in the original FireRed game. If you want to experience these events, you will need to find a way to access them through glitches, modified ROMs, or online emulators.
Remember: Using glitches and modified ROMs can potentially damage your game save file. Proceed with caution and back up your game before attempting to access any events through these means.