Sure! It's an app/game you download which uses the Roms of the different games to enable you to play Pokemon online with other players, but you don't have to engage with them. You can also choose to just play each game as if you were offline and then transition into a new region after the top four, while having access to your pokemon from the old region. It's a lot of fun, but the devs rebalanced the games a bit, which makes it a bit harder, but still fair :) Here's the link where you can find more information: https://pokemmo.com/en/