Foxy Gestures. I love having mouse gestures for Close Tabs on Right, Back, and Close Tab, amongst other.
Zoom Page WE, automatically zoom to full width. Really useful for “convergence” pages, ie: lazy web developers that think every browser wants a 4 word wide column. You have to set “Automatically Zoom” in preferences, it doesn’t work out of the box.
Don’t know if the other browsers have it, but I use Marker by robin-rpr on Firefox desktop. Simple Enough extension for being able to draw/annotate/highlight on browser screen. Was doing some college work in class and wanted to be able to quickly write out and convert binary. Helped so much to be able to do it in browser so I could easily see the numbers.
Though, it was last updated October 22, 2022, so keep that in mind if you’re like me and don’t always like using software that’s more than a few years old (games not included). The alternative I saw (Web Marker by SFer) is under an “All Rights Reserved” license, but was updated last month (June 8th), so pick your poison.
Wayback Machine and also archive.is’s addons. I archive webpages frequently so they’re super helpful. And if a webpage has been taken down you can easily go to an archived version with the Wayback addon.
Also, Vimium C. Not for everyone and definitely down to personal preference rather than “I recommend this to everyone”, but I’d struggle to browse the web comfortably without it.