While Dressrosa has very few pure "filler" episodes (episodes that have nothing to do with the plot), it has heavy "canon-padding" (stretching out manga canon). However, the (Episodes 747-750) immediately follows Dressrosa and is a filler arc that bridges the gap to Zou.
Luffy enters the tournament under the alias "Lucy" to win Ace's Devil Fruit, the Mera Mera no Mi. Meanwhile, the dark underbelly of Dressrosa is exposed as the Tontattas prepare for "Operation SOP." one piece dressrosa arc episode list