Pimp Google Bookmarks is a Greasemonky script and does what its name says: it pimps the Google Bookmarks page and basically does the following:

• Tags on the left are moved into a separate section with its own scroll bar, thus it is possible to scroll down the tags list separately from the content section.
• A double-click on a tag adds that tag / label to the previous search.
• When using up or down key in tags input box a better color is applied to the pull down of tags to better visualize which entry is selected.