A list of Pokémon that are worth hunting down for benefits later in the game.
Make the trade for a Munna-It'll learn Hypnosis pretty fast, which can give you a much-needed breather in the PULSE Tangrowth battle. Alternatively, when the Kricketot you get as a gift evolves, it can learn Sing for the same purpose.
Okay, having played a little more in, I have to say-You need Kricketot on your team in the Beryl PULSE Battle, because Fury Cutter will be your best friend. STAB super-effective against half the team, with doubling power after each hit. Cradily falls in two turns, and Espeon and Umbreon are practically not even there. (unless, of course, they manage to get in a Future Sight or Quick Attack)
Numel-Magnitude and Flame Burst can help you make the most of Cave and Forest Field effects, which will come up soon.
Slurpuff. It's already adorable enough that you should want it for that already, but Fairy Wind will also let you breeze through the Scraggang battle with 4x effectiveness.
Slugma. Same story as Numel, but not only does it get Clear Smog for Misty Fields instead of Magnitude, but it'll also have Flame Body for the eggs you'll have picked up.