- Timelense preview for youtube: https://timelens.io/youtube/ (needs greasemonkey or something)
- Opens pdfs in my pdf reader right away: https://add0n.com/open-in.html?from=pdf (invert sumatra pdf on windows and you even have a dark mode: "...\SumatraPDF.exe" -bg-color #000000 -set-color-range #FFFFFF #000000 )
- (there is also one to open in chrome, really good if you are using FF but need to use google products like meet or jamboard)
- TTS with amazon polly support (if you have an AWS account): https://chrome.google.com/webstore/detail/read-aloud-a-text-...
- oh and mouse users should always scroll my dragging right-click IMO :) https://addons.mozilla.org/en-US/firefox/addon/scroll_anywhe...
- adblock for youtube sponsored bla bla within the video https://sponsor.ajay.app/
- backup what you typed in form fields: https://addons.mozilla.org/en-US/firefox/addon/textarea-cach...
- stylish if you know CSS. I made wikipedia look more like the mobile version, make visited links visible globally, hide jira crap for sprint plannings etc.
- for good keyboard hint navigation: trydactyl (but saka keys is probably more beginner friendly)
- Show which links are fresh on news sites (e.g. on HN). FF only for now though. Just published it myself: https://addons.mozilla.org/en-US/developers/addon/seen-it-al....