Mupen64Plus-Next Transfer Pak?

[LettersFrom]

Is it possible to use the transfer pak on something like pokemon stadium 1&2 to have access to gbc games to be able to use your mons in the stadium games?

[The Trash Dragon]

Yes, it is. You have to have both the ROM and save file in the same place as the Stadium 1/2 Rom, and the names all have to match the Stadium file's name. For example:

If your game is titled "POKEMON STADIUM.z64"
Your Pokemon Blue ROM file should be called "POKEMON STADIUM.z64.gb"
And your Blue's save file should be called "POKEMON STADIUM.z64.sav"

If your save file is a .srm, just rename the extension. GBC files still need to be labeled .gb, this applies to Gold Silver and Crystal. I have no idea if it's possible to have more than one game loaded at a time.