The option to order library filters in groups/folders.

[hiccup]

When you have a lot of library filters, having them all in one single listing takes up lot of vertical space, and makes it difficult to navigate through.

I am aware that auto-playlists can do something similar, and they can be ordered in groups, but the problem is that they will only be available for one single library.
Library filters can stay in place and will function for whatever library you have open.
And it's also very simple to copy them from one MusicBee install to another.

[TateB]

+1

I would add, not just ordering them, but organizing them into folders.

For instance, I have several filters related to "Library Maintenance" or "Tag Maintenance" and a number that aid with "Playlist Management" and still others that are intended to filter particular songs for various other reasons.