Review for Nostalgy by Hagai
Rated 5 out of 5 stars
Nostalgy is a must. Alternatives are not coming close. Quick Folder Move, for example, has no prediction, no keywords, no shortcuts, no string matching for account names, no was to limit to account, no meaningful sort, and no keyboard support for switching between folders.
I realize that maintaining it takes time and not being a paying customer puts me at no position to ask for its maintenance, so I would just recommend that the author establishes some crowd funding campaign that will allow us all to chip in.
To create your own collections, you must have a Mozilla Add-ons account.