NetSurf - A browser that blocks all backend code and most Javascript, which means none of big tech websites can be accessed with it. This is good for browsing what some call The Spartan Web, and Neocities sites like this, so you're not tempted to fall back to social media or whatever else you do online.
Kristall - A nice all-in-one SmolNet browser, supporting Gemini, Gopher, Finger and even text-only HTTP and HTTPS websites.
wApua - The only WML browser that works on modern systems. Even then, Linux only.
Gerbil - A Gemini and Spartan Protocol (Not to be confused with The Spartan Web) Browser
Wayback Machine (iOS | Android) - Not as good as TheOldWeb browser, but this is another okay option for exploring archives websites
Search Engines
Ecosia - Not the most privacy focus engine, but it does plant trees, giving you a peace of mind that you're doing a wee bit to help stop or at least slow down Climate Change
Email, RSS & Newsgroups
Betterbird is a good alternative to Thundebrird with many QoL improvements. I use it daily for my emails, newsgroups and RSS uodates!
RSS Notifier Tools
If you'd rather use something in the background to notify you of RSS feeds, then check these out.
Matrix (Fluffy Chat | Nheko | Element) - A nice, federated chat system that has good chatrooms to hang out in, and some are even bridged to Discord!
XMPP (Dino | Yax.im | Monal) - Another decent federated system. Used to be used by all of the big names, Skype, Facebook, AIM, Google Chat, etc., but those have gone proprietary since, but the open system they used to use remains, and is still active.
Syncterm - A modern BBS browser. Yes, they're still a thing, and it's glorious!
Newsgroups - Newsgroups are also still a thing, but aren't as active as BBSes or XMPP, but you'll see some communitys going about. I use Betterbird to access them.