Board Thread:General Discussion/@comment-35653593-20180819124423/@comment-24922135-20180820165413

Whether filler is canon or not is on a case-by-case basis even in anime, not all anime with filler is an adaptation, not all filler is anime-exclusive when it is an adaptation.

As it happens I kinda agree that this category isn't really useful here since Ben 10 has more "filler" than it does plot. Since the plot itself is usually fairly loose, I'd go as far as to say Ben 10 doesn't have filler.