Ublock Origin is the only mandatory extension i can think of.

Some other extensions I personally use are:

Gesturefy is useful if you want to control things with mouse gestures (holding right-click and then drawing a shape to activate commands)

NoScript for a little added security, with the cost of having to manually enable javascript on websites that literally can’t function without it.

Any extension that runs userscripts.

Dark Reader for websites that don’t offer a dark mode.