To add a bit of flavor, Nintendo/Game Freak has allowed players to migrate Pokémon from the current game generation to the next one for every game generation with the sole exception of Generation 2 (Gold, Silver, Crystal) to Generation 3 (Ruby, Sapphire, Firered, LeafGreen, Emerald)
Players could migrate Pokémon from the virtual console re releases for Red, Blue, Yellow, Gold, Silver, and Crystal to Gen 6 and onward, but never to Gen 3, 4, or 5. Furthermore, there was never an official way to use your Gameboy Cartridge saves on the virtual console.
For players lucky enough to have their Pokémon save batteries still living, this is an opportunity for them to save their Gen 1 and 2 Pokémon.
Players could migrate Pokémon from the virtual console re releases for Red, Blue, Yellow, Gold, Silver, and Crystal to Gen 6 and onward, but never to Gen 3, 4, or 5. Furthermore, there was never an official way to use your Gameboy Cartridge saves on the virtual console.
For players lucky enough to have their Pokémon save batteries still living, this is an opportunity for them to save their Gen 1 and 2 Pokémon.