Decidueye

Decidueye is the Grass starter of Gen 7, and a popular Pokemon among players of Sun and Moon. Unfortunately at this time Decidueye sits in the shadows of stronger Grass-type attackers already in the game, making it a Dex filler at best for now.

Best PvE Offensive Moveset

• Magical Leaf and Frenzy Plant* is the best moveset for Decidueye
• Astonish and Spirit Shackle is... okay. It can work for a Ghost Type moveset, but it's not great.
• Razor Leaf, Energy Ball, Leafage, Shadow Sneak, and Brave Bird all fall behind.

Best PvE Defensive Moveset

• Magical Leaf easily out-paces Astonish, Leafage, and Razor Leaf on defense.
• Go for Spirit Shackle for defense, as it comes out far more frequently than the other options.
• Frenzy Plant would be okay, but pairing it with Magical Leaf leaves Decidueye very easy to take down by anything that resists Grass.
• Energy Ball is basically Frenzy Plant, but worse.
• Shadow Sneak is literally Spirit Shackle, but worse.
• Brave Bird probably won't come out before Decidueye bites it.

Of the three Grass-type Fast Attacks that Decidueye has access to, Leafage is overall the best option. It has the highest energy generation, fueling Decidueye's good Charged Attacks. Having a shorter duration than Magical Leaf also allows Decidueye to be more flexible when it comes to move timing and catching. Razor Leaf's high DPT may be tempting, but Pokemon such as Shadow Victreebel and Tropius are more suited for that role.

Astonish has been buffed repeatedly and is a decent move choice now, should Decidueye want to lean into its Ghost typing more.

Frenzy Plant continues to be one of the best attacks in the game. Spirit Shackle, Decidueye's signature move, is its cheapest Charged Attack and is a much better move than Shadow Sneak. Brave Bird is a solid move and can potentially be a situational choice over Spirit Shackle, but it is a far less reliable move. Energy Ball is simply outclassed by Frenzy Plant.