My favorite addon, although i use others that are 'essential', which i would have to choose first, but this one is most important for my daily browsing on youtube, as I could manually skip ads, or ignore tracking, or remember my passwords, or get used to white background.
. there are many BS youtube channels that are just so mediocre or legitimately fake/false.

Need ONE thing though, curated lists of things to block, like an adblocker.