The addon doesn't need to work with Volumes from what I can see because volumes are reading external data or meshes inside of Blender. technically this already works as long as anything with vertices is working.
Clear is not working with normal clearing and selections
Meta Balls
Sufaces
Grease pencil objects
Supports Layers
frames need to be looked at. Currently, grease pencil doesn't retain the information of draw mode or edit mode. I'm not sure if I can see any use in supporting Grease Pencils. Switching out the layer count could be really handy for masking in grease pencil.
Text. when it comes to text we could still use the same rule for selections based on the highlighted text.
The addon doesn't need to work with Volumes from what I can see because volumes are reading external data or meshes inside of Blender. technically this already works as long as anything with vertices is working.
Clear is not working with normal clearing and selections
Meta Balls
Sufaces
Grease pencil objects
Text. when it comes to text we could still use the same rule for selections based on the highlighted text.