Is ONE PIECE episode 466 filler?
Canon No, episode 466 of ONE PIECE is canon.
#466
Straw Hat Team Arrives! Tension Grows at the Battlefield
麦わらチーム到着 風雲急を告げる戦場
Aired 12 Sept 2010
Mochibayo compiled this list from MyAnimeList's labels, because MyAnimeList's episode data is not reaching us at the moment.