Mega Altaria is out and about! It’s important to get enough mega energy to evolve at least one, they have many bonuses now, and you never know what will change. As far as raids, it’s unlikely to shine in PvE, being outclasses by other options. For PvP, it’s long been a staple in great league, while it can get countered hard, it really shines outside of those loses. If you have battled one without having a good counter to it, you know how annoying they can be.
What to use? Fairy and Dragon typing makes this a strange one, it now resists dragon damage, making the mighty Metagross top of the picks again with its anti fairy steel moves. Steel and Ice will be your heaviest hitters, with poison making it’s rare appearance. Mega Gengar and Beedrill are very heavy hitters, but a Mega Abomasnow will boost fellow ice types. I hope everyone has a Mamoswine, it’s a nice budget attacker that pops up quite often.
Go to the official counters page for a complete list, including shadows and megas to see how your Pokémon perform.