(Sadly userecho won't let the community self-organize and propose merges to duplicate suggestions...)
Even without automated duplicate removal, sorting the lists (either globally, or by Group/Window/...etc) would be a key step to enable folks to clean up their own lists. Please consider.
There's a whole lot of related suggestions here for sorting that mostly revolve around cleaning up duplicate / large tab lists.
Sort folders alphabetically
Sort tabs in windows
Option to sort last opened urls
Make it easier to edit/delete
(Sadly userecho won't let the community self-organize and propose merges to duplicate suggestions...)
Even without automated duplicate removal, sorting the lists (either globally, or by Group/Window/...etc) would be a key step to enable folks to clean up their own lists. Please consider.