https://pokemmo.eu/
You can do Kanto and/or Johto, just like original games but you can see all the other nerds and challenge them to battle and there are EV/IVs implemented. Before you waste the time getting through it you better look up the breeding guide though, they made getting decent IVs 1000x more grindy than in the real actual game. ALso there's only one mewtwo on the server and you can only keep him until you are defeated in battle, king of the hill sort of deal.