My primary browser is currently Vivaldi, but I have recently started the search again for a new one because it seems that after a couple hours of youtube my computer cannot do anything... Which just means that I still mostly run chromium extensions
Adguard AdBlocker I am not super picky about my ad blocker, and I generally leave acceptable ads turned on for blockers that support it
Ghostery Privacy matters, and I am suspicious about the many trackers that are all over everywhere...
Magic Actions for Youtube This one is probably my favorite- I get volume control with my scroll wheel, it can disable autoplay, force the html5 player, and really why I use it: I can resize my browser window, and it will fullscreen the youtube video only to that browser window! I used to do this by modifying the url to have "embed" in it, but this only worked on some videos and did not let me undo it to look at the comments. Also available for firefox
Best video downloader 2I haven't used this in a while, so I don't know if it will still work, but this is the only youtube video downloader I have found that works on chromium-based browsers. Firefox, on the other hand, has very many in their add-ons store.