>>20734492>>20734856Quick Attack is the best move on Sylveon.
0- Atk Pixilate Sylveon Quick Attack vs. 40 HP / 0 Def Mega Heracross: 66-78 (21.2 - 25%) -- 0% chance to 4HKO
0- Atk Pixilate Sylveon Quick Attack vs. 0 HP / 0 Def Garchomp: 74-90 (20.7 - 25.2%) -- 0% chance to 4HKO
0- Atk Pixilate Sylveon Quick Attack vs. 0 HP / 4 Def Dragonite: 74-90 (22.9 - 27.8%) -- 60.7% chance to 4HKO
(After breaking Multiscale)
0- Atk Pixilate Sylveon Quick Attack vs. 4 HP / 0 Def Greninja: 102-120 (35.6 - 41.9%) -- guaranteed 3HKO
(Before it changes from dark type)
If that's not convincing enough, I've played around with the calcs. Using a hindering nature on Sylveon, but factoring in the Pixilate boost, Quick Attack is the equivalent of a 30BP fairy type move. Weaker than the average priority, yes, but it's a STAB priority, and fairy hits quite a lot of things supereffective. It's far from shit.