The following is a list of free tools I recommend for protecting your privacy online from advertisers, your ISP, social media companies, and others. For a broader discussion on privacy, check out my 2016 talk at Open Twin Cities.
TutaNota: A privacy-conscious email provider based in Germany, a country with stronger data privacy laws than the US. The free plan gets you a firstname.lastname@example.org address with 1 GB of storage. Unlike Gmail, TutaNota cannot scan your emails to display targeted ads, because your emails on TutaNota servers are encrypted at rest. (See limitations.)
ProtonMail: A more well known privacy-conscious email provider based in Switzerland, protected by Swiss privacy laws. The free plan gets you your own email@example.com address with 500 MB of storage, but all of your sent emails have a required “Sent with ProtonMail” signature. The paid plan is about $60 per year. (See limitations.)
Tails: A privacy and anonymity-focused operating system. Typically, Tails is installed on an external USB drive, and run on a computer, without replacing or affecting the OS inside the computer. Tails is a Linux OS, so there’s a bit of a learning curve. All internet usage on Tails is routed through Tor. It’s like the Tor Browser, but for the entire OS. More information can be found here.
Tor Browser: The most secure web browser, Tor Browser routes all your traffic through the Tor Network. This means that your ISP can’t tell what you’re browsing, and the websites you visit will not necessarily know who you are. However, Tor Browser is not all you need to browse anonymously.
Firefox: For more standard web browsing, Firefox is the most popular free and open-source web browser. Unlike Chrome, it won’t scan your files. Firefox is FOSS software developed by Mozilla, a non-profit organization.
uBlock Origin: The most popular and most effective content blocker, blocking targeted ads, third-party trackers, malware, and more for Firefox, Chrome, Opera, and Edge. There is also a Safari experimental version. Beware of mixing up uBlock Origin with “uBlock”, which is outdated.
Privacy Badger: A content blocker that is similar to uBlock Origin, but it only blocks trackers and ads that track you. Developed by the Electronic Frontier Foundation, it is available for Firefox, Chrome, and Opera.
HTTPS Everywhere: Another extension by EFF, HTTPS Everywhere redirects you from HTTP to HTTPS when it’s available, increasing your privacy. Available for Firefox, Chrome, and Opera.
Decentraleyes: Helps avoid being tracked by third-party CDNs. Available for Firefox, Chrome, and Opera.
FreeOTP: A free and open-source authentication app for iOS and Android that is an alternative to Google Authenticator.
Authenticator by Matt Rubin (iOS only): A simple, beautiful authentication app that is an alternative to Google Authenticator. It is free, open-source, and never connects to the internet.
Where to go from here? PrivacyTools.io has much more detailed lists of privacy tools, both free and non-free. They cover additional categories like VPNs, decentralized social networks, and password managers. In addition, /r/privacytoolsIO/ is a great place to ask questions about privacy tools.