Is Bleach episode 351 filler?
Canon No, episode 351 of Bleach is canon.
#351
Fullbring, The Detested Power!
フルブリング、忌み嫌われた力！
Aired 6 Dec 2011
Mochibayo compiled this list from MyAnimeList's labels, because MyAnimeList's episode data is not reaching us at the moment.