This list covers privacy and security related extensions only. While we believe these are the very best of the best, this can be subjective depending on your needs. We are also not saying you have to use all these extensions.
Extensions (in no particular order...)
uBlock Origin ✔ Privacy
Temporary Containers ✔ Privacy
This can achieve almost everything First Party Isolation (FPI) does without breaking cross-domain logins. And (with or without FPI), in a hardened TC setup, this can even isolate repeat visits to the same domain, which FPI alone cannot.
Required reading: [1] AMO description [2] Article [3] TC's Wiki
Smart Referer ✔ Privacy
Header Editor
Allows you to run Rules to modify modify the request header and response header, cancel a request and redirect a request. Be careful not to alter your passive fingerprint
I use what the Arkenfox project recommends:
Plus I also use Gesturefy and Behind!