Melmetal

This deck relies heavily on getting Meltan on the field turn 1 and getting the Caterpie line on your bench quickly, but if done properly it can easily result in a Melmetal that regenerates 40 HP every turn, effectively negating 60 damage and allowing it to rampage. This can potentially rise to 80 with a Potion use, allowing it to wall out Pikachu EX and Starmie EX. Odds are against this deck, but when the stars align, it can outright crush some strong meta decks, and it's probably going to take something capable of dealing 150 or more damage in a single move to put down effectively.

A pure-Metal deck is easy to overlook, but it can be effective. The goal here is the same as most Melmetal decks; get Meltan on the field, and build energy with Amass. However, this deck can also potentially stall out the opponent and build up Melmetal on the bench, as Mawile has the ability to force a stale-mate if it comes in against an opponent with an energy deficit of 1 or more energy as a good coin flip discards 1 energy. Add to that a relatively low-cost Bisharp to clean up the field or do a bit of damage before Melmetal begins its rampage, and this deck can actually clean up pretty nicely, and potentially disrupt long enough for its headliner to come in and start doing its job.

Only use Metal energy, Hypno will only use his Sleep Pendulum ability to stall while you get Melmetal in place. Mawile also helps stall by delaying the opponent's energy build-up. You typically want at least one use of Amass on Meltan before evolving.