This is my list of must have extension or addons for my browsers, i’m using quite a lot of browser, mostly for testing, my main browser still Firefox Quantum and Google Chrome, but it can be installed on most major browser, even Brave or Vivaldi can.
People forget their password most of the time, using different password for different website is a secure way to protect your account, but to remember all of them is hard, that’s why password management like 1Password come handy, mind you that this is a paid service. but you could install another password management like Lastpass.
This one is a saviour, you browse one website, the hyperlink sends you another one and another one, and you ended up with 32 tabs opened, Onetab will save your opened tab and close it, and you will regain your precious CPU and RAM.
Like Privacy Badger, uBlock origin also remove ads from website with less CPU, and quite efective than Adblock Plus or its variant.
That’s my five must have extension/addons and most used, there’s quite a lot of other addons that useful for development or productivity out there.