Starting to think many don’t really know what a filler episode is if they think all of these are filler. A filler episode isn’t just a one-off story, but normally something that just feels like it is utterly forgettable and disposable and mainly there to fill out the schedule because the writers didn’t have any better ideas. Episodes like Move Along Home, The Storyteller, Second Sight, The Muse, Let He Who Is Without Sin, Resurrection, Profit and Lace, etc. The type of episodes many will just skip on a rewatch.
There is a difference between a filler episode and a character episode.