Cottonee

Charm + Seed Bomb & Grass Knot

Charm holds a special place in most metas due to its pervasive power and huge 5.33 Damage per Turn (DPT), offset a bit by its 2 EPT (Energy per Turn), and Cottonee is the best user of the move in the Little Cup meta. Seed Bomb (55 Power/40 Energy) is not the strongest move overall, but it's Cottonee's cheapest move option, which is important given Charm's low energy gains. Grass Knot (90 Power/50 Energy) is a bit more expensive to use, but its damage increase is very significant.

Razor Leaf + Seed Bomb & Grass Knot

Razor Leaf is the single highest damage fast move in the game at 5.5 Damage per Turn (DPT) and 2 EPT (Energy per Turn). However, the wide coverage of Fairy and the poor coverage of Grass in the meta generally makes Charm a better choice. Basically, Razor Leaf is only desirable if you need to counter a Water Type.

Charm + Seed Bomb & Energy Ball 

Instead of using Grass Knot, the alternate Energy Ball has the same damage, but is 5 energy more expensive. For this reason, it's generally not recommended. However, it does run a 10% chance of dropping enemy defense, which can make Cottonee's Charm far more powerful. That said, it's probably best not to run this set by comparison.