Gallade

The Blade Pokemon of Gen 4 received the appropriate Leaf Blade, though the rest of its moveset really holds it back from being relevant in the meta. While it does have access to two different double STAB movesets, the sub-par options of Low Kick holds it back as a fighter, while Psychic is nice, but doesn't raise Gallade to the top echelon of Psychic Type attackers. The addition of Charm from the July 2019 move rebalance doesn't change much due to a lack of STAB, and Synchronoise was outclassed by a rebalanced Psychic not long after

Best PvE Offensive Moveset

• Confusion pairs well with Psychic to fulfill a Psychic attacker role. 

• Psycho Cut has lower power, but allows for easier dodging.

• Low Kick works with Close Combat, but there are many better Fighting type attackers. 

• Charm lacks STAB and doesn't have much use for Gallade's role. 

• Leaf Blade has little to no utility on Gallade.

• Synchronoise is Psychic, but worse.

Best PvE Defensive Moveset

• Charm and Confusion are both top picks for Gallade on defense. The former offers strong coverage against many common gym attackers, while the latter offers stronger neutral power.

• Low Kick and Psycho Cut have very poor damage output on defense. 

• Leaf Blade is Gallade's only multi-bar charge move and is most likely to be used before Gallade faints.

• Psychic is a strong move, though it's not as frequently used as Leaf Blade. 

• Synchronoise is Psychic, but worse. Its one saving grace is that it's a bit harder to dodge.

• Close Combat is inferior. 

Psycho Cut is the preferred fast move for Gallade for its incredible energy generation, synergizing with its powerful Charged Attacks. Confusion is an okay move; its high DPT helps improve Gallade's overall coverage, but it won't reach its deadly Charged Attacks anywhere as quickly. Charm may have incredibly niche uses in certain rulesets due to the heavy Fairy-type damage it deals.

Leaf Blade (2.0 DPE) is one of the best charge moves for PvP, and is almost essential for Gallade even if it lacks STAB. A very low 35 energy cost of means Gallade only needs 4 Psycho Cuts to be able to use it. Close Combat provides key coverage against Steel, and it's extremely powerful (100 damage for 45 Energy) but complicated to use, due to the big Defense debuff that it triggers at each use, especially damning on an already frail pokemon like Gallade.

What about Synchronoise? 

Synchronoise is an exclusive move featured during Ralts Community Day. It costs a modest 50 energy, sports a respectable 1.60 Damage Per Energy (DPE), and gets STAB on top. However, it is typically not recommended because Leaf Blade and Close Combat are extremely good moves and finding room to replace either is difficult.