Himeo
Vyemm Raider
Some filler episodes/arcs are wonderful. One piece episode 384 stands out, as one of the best filler ever. It's entirely character development, showing what each of the crew do in an average day on the seas as a new member tries to fit in.I don't get it, why would anyone bother watching filler episodes. You already know it's not cannon and there is no character progression.
The G8 filler arc in One Piece was better than half of the cannon arcs.
I'm sure you could find more in other series.