Download full size infograph here.
Dialga is here! It’s a great shiny, super useful in Master League PvP, Grunt battles, and a top counter in many raids. All your friends want them in trades, so you really want a few of these things.
What to use? Where are the Mega? Charizard Y comes close, but isn’t as good as any of these counters, and not the right type to boost. A Mega Bunny gives the fighters that extra bonus, and is a decent counter on its own. Mega Steelix? Not a top counter, and the bonus is probably wasted by the poor damage it does on it’s own, if there are enough that the mega boost helps, you don’t need it. We’ve all got fighters, right?
Go to the official counters page for a complete list, including shadows and megas to see how your Pokémon perform.