Move: Fling [Dark type]
Item: Iron Ball
Fling is a move that allows the Pokemon to throw its held item at the foe. The Iron Ball is an item that lowers your Speed and makes Flying and levitating Pokémon prone to Ground type moves. Despite these negative effects, Fling's power is 130 when you throw this heavy item.

Move: Trick [Psychic type] or Switcheroo [Dark type]
Item: Choice Scarf
The item Choice Scarf boosts the holder's Speed, but only allows one move to be used. Use Trick or Switcheroo to swap items with the opponent so THEY suffer the effects of the Choice Scarf.

Move 1: Sunny Day [Fire type]
Move 2: Solarbeam [Grass type]
Solarbeam is a powerful move with an attack power of 120, but it takes two turns to fire. When the weather is sunny it only takes one turn to fire, so use Sunny Day to make it nice and sunny, then fire away!

Pokemon: Castform
Move 1: Sunny Day [Fire type], Rain Dance [Water type], or Hail [Ice type]
Move 2: Weather Ball [Normal type]
Castform is a unique Pokemon that can change form depending on the weather. It changes into the Sunny form [Fire type] in sunny weather, Rainy form [Water type] in rainy weather, and Snowy form [Ice type] in hail weather. Weather Ball is a move that changes type in accordance with the weather, so if there was a Fire type Pokemon, you can make it rainy and inflict double the damage on that Pokemon using Weather Ball. When there's a Grass type sent out, you can then change the weather to hail weather and use Weather Ball again.