Leavanny

Leavanny definitely exists!

This generation 5 mantid Pokemon has almost nothing to differentiate itself from its competition. As a Grass Type attacker it's badly outclassed by basically anything with Frenzy Plant, much less Pokemon like Roserade. On the Bug side, it's actually beaten out by Scyther. Not just Scizor, Scyther. Its unique typing is the only torch that it can carry, and even that is more of a liability than a blessing because - OH LORD IT DROPPED THE TORCH AND IS ON FIRE!

Best PvE Offensive Moveset

• Razor Leaf and Leaf Blade go together for a Grass Type set.
• Bug Bite and X-Scissor go together for a Bug Type set.
• Leaf Storm is a downgrade. 
• Silver Wind is inferior.

Best PvE Defensive Moveset

• Razor Leaf is the fast move of choice due to its high base damage. Bug Bite is inferior in most cases.
• Silver Wind comes out frequently and has high damage
• X-Scissor is faster, but the damage difference is substantial
• Leaf Blade is objectively good, but having the same type as Leavanny's best fast move makes it easy to wall.
• Leaf Storm is too slow to access for defense. 

Shadow Claw*, Leavanny's Community Day move, outclasses both Razor Leaf and Bug Bite thanks to its superior parameters and added coverage against Steel- and Poison-type Pokemon.

Leaf Blade is one of the most efficient charge moves in the game, offering incredible damage output for the lowest amount of energy possible. X-Scissor falls behind considerable in terms of damage, but also ties for the least amount of energy needed, and provides different coverage. Silver Wind is a very poor move, despite STAB. Leaf Storm is inferior to Leaf Blade.