This post contains good Firefox and Google Chrome Extensions to use to help maintain better privacy when browsing the web.
Here's a good explanation on the differences between Extensions, Add-Ons, and Plugins.
Most folks should be familiar with an Ad-Blocker. uBlock Origin blocks ads, thus making pages load more quickly, and reduces the possibility of being tracked as you traverse the internet.
Be wary of other similarly named browser plugins that imply they will block ads,
Multi-Account Containers (Firefox)
This is an incredible feature for privacy. In reality, the pages we visit on the internet can see information about each other in your browser. Even if you're running multiple tabs in Incognito Mode.
While not the most intuitive extension out there, this lets you group websites into groups, or containers, so that not everything you come across on the internet can snoop on other tabs, windows, or cookies. It helps you to group your Banking tabs into one container, so it's kept far away from any site you might click on during a Google Search. Also, put your Google tabs into Google Container so they can't track your activities quite as easily.
The options are limitless.
HTTPS Everywhere is an extension created by EFF and the Tor Project which automatically switches thousands of sites from insecure "http" to secure "https". It will protect you against many forms of surveillance and account hijacking, and some forms of censorship.
This extension blocks the ability of 3rd parties to track you by fingerprinting your browser (via HTML5's canvas) and phoning home to the mothership as you browse sites on the web.
This is a great extension that lets you automatically delete browser cookies that can be used for tracking. You can whitelist certain domains so it doesn't behave the same way for every site e.g. (Don't get logged out of Amazon if you close all Amazon tabs).
Random User Agent
Be careful with things like Youtube and the Random User Agent. Out of all of these plugins, I have to disable this one the most often because of how it confuses the website you're visiting.
Web browsers come in many shapes and forms: on a PC, Tablet, Phone, Refrigerator... So it's for a webserver to know what kind of browser you're using, to give you the best experience.
Since this extension randomly chooses the
User-Agent, it's essentially pretending to be a random browser/device - and some sites just can't have that.