Instanced Keyframes for Grease Pencil

what all other 2d animation software have, but GP doesnt, are instanced keyframes. Means if you reuse a drawing, like its often done in 2d animation, and later refine it on one keyframe it gets reflected to the instanced keyframe(s).

This has been a standard feature in any 2D software i can think of and pretty useful and widely used too.

For example: if you need to update the mouthshape of your character , you have to go over all keyframes and replace them one by one for the whole shot .. every time you make a small change and need to evaluate it in motion. for a character and its compexity this can easy amount to hours of overhead.

this affects all reusable details , like eyes , mouth etc. but also effects like fire, gunfire, rain everything where a keyframe is duplicated and used more than once basically.

sure i could build it into a rig through a bone which maps to the keyframes and then animate that , but thats not the spirit of 2D and you loose your flow always tapping out of the gp object and into your rig.

A GP keyframe is not just a keyframe where a property of a baseobject is tweened , it holds all the relevant and visual content by itself. Its not a keyframe in the 3d sense with just a tweaked value, but its an actual drawing - the object or figure itself in a sense. and objects should be able to be instanced.

In other 2D apps the DRAWINGS are therefor enumerated and can be accessed through a spreadsheet/list. Blender should already do that in the background but theres no UI to access it . On the Dopesheet it could look like ^7, when its linked to drawing number 7

the simpler option to solve this would be something like "select duplicated keyframes" , and then use multiframe mode to edit/sculpt/redraw them all at once. but thats the ghetto solution