Thank you for your review, I'm glad you find it as useful as I do.

For a "list view", in the preferences there is a "Compact mode" that makes each bookmark take 1 small line instead of a big square, this might be what you are looking for.

What you describe for tab list, and turning tabs into bookmarks, is something I have been thinking about and trying to do for some time, to tackle the tab hoarding problem. I even had a system that would automatically close tabs and turn them into bookmarks, if they were open for too long. A tab list feature would be easy to do. But I'll also have to implement some kind of multi-item drag-n-drop system, that I suspect will be harder to do correctly. This might be one of the reason the bookmark window in Firefox hasn't really changed in ~20 years.

For a search/filter system, for now the best alternative is to use the browser's URL bar, with "*" + your search term, but since other users have been asking me about it, I'll check in Firefox's documentation if I can implement my own search feature.