I built this for personal use, but maybe someone else also finds it useful.
It's a Firefox add-on that arranges YouTube video tabs based on the runtime of the video. I often hoard many YouTube tabs and at some point I want to either watch the shortest ones or play something lengthy so I can do household chores while listening to the video. This makes finding the correct video from tens of different tabs so much easier. There is one known major bug: if a video is playing, the sorting doesn't work.
There is an older version published for Microsoft Edge, but Edge Add-ons started rejecting the updates based on unclear reasons (something along the lines of "no value for user" ???). When reaching for support through email, I only get responses from people who don't understand English and just copy-paste the exact same unclear rejection report and close the ticket.
Chrome Web Store has a publishing fee and outright rejects me paying it, probably because I live in Switzerland and my credit card is from a Finnish bank.