Review for Mailing List Manager by rjohnson19
Rated 3 out of 5 stars
On first run, the add-on indicated it would index my Inbox folders for mailing list. But I already had mailing lists in other folders. It seemed to pick them up after I opened the folders.
It did miss one of my mailing lists. Overall I like the idea, hopefully it can replace manual mailing list management for most people.
Two issues I found: It took over a pre-existing "Mailing Lists" folder in my Gmail IMAP account, and when disabled, the pref mailnews.headers.extraExpandedHeaders value causes list headers to always appear. Not sure if this is cleaned up on uninstall.
To create your own collections, you must have a Mozilla Add-ons account.