Anime Filler ListS
Manga Canon
Based on Manga i.e official work
Manga Canon are those episodes that contain the main element of Anime and are also in manga officially approved by the creator.
Anime Canon
Anime Canon not in Manga
Anime Canon is also the main story but if you are reading manga you can skip these. Actually, these are canon for anime viewers
Filler Episodes
Not Related to the main story
Filler episodes are not related to the main story you can skip these. Anime Filler episodes refer to those which are not part of the manga.
Mixed Canon/ Filler
A mix of both i.e max canon
It is a way to make the episode bigger and give time to the creator by having a canon material with a flashback of the past but you have to see these
Here is a complete Filler List so you can avoid each and every filler episode.