I just found this mod and it already feels like one of those that in the future I can't play Factorio without! So thank You, first of all :)

My two suggestions would be:
- Add a way to filter for more than 1 item. The simplest way I can think of would be to append the filter list by the item hovered over if Control + D is used again with the Deconstruction Planner in hand. (Maybe even make it toggleable, if the item is already in the filter, Control + D removes it?)
- Bring the functionality to Copy (and Cut): "In the marked area, copy only this / copy everything except this"

Hey! Glad you appreciate the mod and thanks for the suggestions!

I will look into implementing adding more entities today, I will send a response when the new version is out!
I think I will leave out removing entities out for now, I think it will be easier to use if you can just mindlessly add entities without worrying about accidentally deleting one.
But feel free to give me feedback on that once the new version is out, I am currently not playing so I am relying on people like you to give me practical feedback!

And about Copy and Cut: I am not sure if I can easily add this feature, as the copy planners (Copy, Cut, Blueprint) don't support filters, so the workaround is a bit tricky.
I will come back to it in the future, the idea is good tho!

Hey, glad you like the suggestions :)
I'm on vacation for the next 2 weeks, so I won't really be playing, after that I'll surely give feedback.
Yeah I had a gut feeling that messing with the Copy/Cut features might be more complicated. Maybe the Copy part could be worked around with using blueprints? I don't know how many people use it this way, but I very often want to copy only certain types of entities of a part of my factory, and I usually do this by copying while holding shift to create a blueprint, then deactivating the undesired entities in the blueprint, and then pasting it. I have a hunch that automating that into a mod might be easier than messing with the regular copy feature. Though I'm not speaking from any modding experience, just a very vague guess from my limited coding knowledge. :) Would be a neat thing to have this as a tool (that does "Create a blueprint containing only the entities I hovered over). That said, the workaround I'm using isn't that much more clunky.
I'm really looking forward to the multi-entity-deconstruction-planner! Setting up a planner by hand to delete one batch of something just to delete the deletion planner after won't be missed. ;)