Rated 5 out of 5 stars
I don't want to take any users away from QFM, but Philipp implied on the Nostalgy github page that he is not updating or extending QFM right now.
Several users mentioned Nostalgy her in the reviews. Manage Emails/Nostalgy++ is finished for TB 78, even with some new actions, I will upload it to https://addons.thunderbird.net/de/thunderbird/addon/nostalgy_ng/ for review tomorrow morning. Review by TB team will probably take a few days.
@Philipp - If you think this message is in the wrong place, please feel free to delete it. I thought the note might help some power users with many folders and rules.