Start adding Tags to your bookmarks when you save them - then you can quickly filter by the tag (enter the term into the Search Bookmarks box) . You can have multiple tags separated by a comma so "watch, Rolex" would be found by searching for either term.

As for collections of bookmarks look into addons like Tabstash. You can group tabs into groups which show on the left side & then you can delete the tab until needed. This is useful for longer projects - I used it when updating a bathroom as I had a Stash for Basins, another for Baths & so on. Rather than have a million tabs open I just had them grouped in the Tabstash column. There are other tab management add-ons but Tabstash was the one I settled on.