Filler means that the storyline of the anime is not part of the manga, or more specifically, not written by the original author. Usually when we say filler we mean that the animation studio uses horrible scripts to "fill" up time to create distance between the anime and manga so that the anime doesn't catch up to the manga too fast.

Anyway, OP filler:

54-60 all, 61 is half filler
131-143 all
196-206 all
220-225 all, 226 is mostly but not all filler