Two pretty interesting browser add-ons/plugins to improve the UX on YouTube:
SponsorBlock is an open-source crowdsourced browser extension and open API for skipping sponsor segments in YouTube videos. Users submit when a sponsor happens from the extension, and the extension automatically skips sponsors it knows about using a privacy preserving query system. It also supports skipping other categories, such as intros, outros and reminders to subscribe, and skipping to the point with highlight.
DeArrow is an open source browser extension for crowdsourcing better titles and thumbnails on YouTube. The goal is to make titles accurate and reduce sensationalism. No more arrows, ridiculous faces, and no more clickbait.