0275 Shiftry

Snarl is one of the fastest charging moves in the game at 4.33 EPT (Energy Per Turn), and that makes for a really deadly combination with Leaf Blade, one of the most powerful cheap charged moves at 70 Damage for only 35 Energy cost. Only 3 fast moves are needed to reach it! Foul Play complements the pair perfectly, with coverage on pretty much everything that resists Grass.

Bullet Seed is a direct clone of Snarl now making this moveset pretty comparable to the above one. The difference is extremely minimal since the moves are played for energy generation, not damage. Bullet Seed can swing a few matchups in the Great League like Umbreon though Snarl is preferred and is better overall.

This moveset is the opposite of the previous one, relying mainly on the damage of the fast move Razor Leaf, the hardest hitting one in the game, which however generates Energy very slowly. Leaf Blade still pairs well with it as it's cheap enough to be reached consistently.

Shiftry sports a relatively unique Grass/Dark typing that gives it advantages over other Pokemon that share similar roles. Access to both Snarl and Leaf Blade makes Shiftry one of the fastest spammers in the game, able to use its powerful STAB charge moves very frequently. Unfortunately poor bulk is quite notable in prolonged battles, which can cause Shiftry to lose fights quickly without any typing advantages.

Shiftry is still a decent pick for the Ultra League, as it will handle the Water/Ground meta like Swampert while having some good coverage for common Psychic and Ghost-type Pokemon. 

Shiftry is a long way from being a top tier pick for the Master League, although it will still have its key matchups. It would be best to keep your Shiftry in the Great and Ultra League.