As far as I'm aware, currently in Krita the only way to apply a filter to multiple frames of an image is to use a Filter mask.
However, there are things that aren't possible with those, such as the G'MIC filters.
Specifically, the ability to use G'MICs newest colorize filter on an animation would be incredibly useful, creating flat colours speeding up the colouring process immensely
but as it currently stands, it has to be applied to each frame separately, with some fussing about with merging newly created layers.

Is it possible for filters to be able to be applied to all frames of an animation?
I would personally love for this to be the default behaviour for applying a filter to an animated layer,
and several of my animator friends have expressed that they would be very interested in that too.