Hint 1
Your move. And, remember, accuracy is not important here, but power is.
Hint 2
The generation of these Hoenn diagrams was not straightforward. We had to look at what was shaRED in order to make this a good contest.
Hint 3
The images clue for Pokémon moves and have been arranged in sets based on a certain feature. Identify what the features represented by the sets outlined in red are, and find the move that is present in all three red sets.