This page draws up a non-exhaustive list of newsreaders meeting the following criteria:
Some newsreaders have a graphical interface, others are used in text mode, sometimes in a terminal window (in this case, their configuration is done on the command line).
Although development of 40Tude Dialog has been stopped for a long time, it remains perfectly usable on recent versions of Windows. Its official site no longer exists, but its very latest version has been carefully archived on the French site Gratilog.net:
40tude Dialog 2.0 Beta 38 (Built 2.0.15.1) (Fr)
Also note the existence of this archive:
There you will find (functional) download links, a FAQ and above all a copious list of scripts allowing you to add features to 40Tude Dialog.

Some of these scripts may not work, and some need an additional library, available at the bottom of the Downloads page.
Betterbird is a fork of Thunderbird created by a former Mozilla developer. Among the added features, some had been hoped for for a long time, including searching for a message by its identifier and managing the non-breaking space (which mainly concerns French-speaking users).
If necessary, translation packs are extensions to download separately.
Claws Mail is both an email software and a newsreader. Regarding news, it turns out to be a little more complete than Thunderbird, while being lighter. Claws-Mail is a fork of Sylpheed.
Evolution is an application integrated into the GNOME desktop environment, combining an email client, a calendar and, for what interests us here, a newsreader. Its interface is quite similar to that of Betterbird / Thunderbird.
flnews is a light but effective newsreader.

The current version of the 'application bundle' proposed for macOS seems incompatible with certain versions of the system, or perhaps with certain processors (does not work on an Intel Core i5 iMac under macOS 10.14).
Gnus is a newsreader integrated into the Emacs text editor. It has very advanced features but can be a little difficult to master.
Gravity is a newsreader initially developed by the company MicroPlanet and whose code became open source in 2003. Some (minor) encoding flaws should be corrected.
The arrival of MacCafé in 2020 filled a gap caused by the incompatibility of the MacSOUP newsreader (see below) with recent versions of macOS. Version 3.02, released in June 2024, adds an English translation of the interface.

MacCafé is an 'offline' newsreader, meaning it downloads and archives the full articles (header + body).
Apple stopped supporting 32-bit applications — including MacSOUP — starting with macOS 10.15 (Catalina). This newsreader must therefore be reserved for earlier versions of the system.
The official MacSOUP website no longer exists, but Jean-Pierre Kuypers has kindly posted the latest version online, accompanied by a French translation of his own.
Although MesNews was specifically designed for Windows, it can be easily installed on Linux or macOS, via Wine. Like Gravity, MesNews suffers from a few minor encoding flaws.
This newsreader for Android is a modified (and ad-free) version of PiaoHong's NewsGroup Reader application. Several versions are circulating, the most recent and most complete appearing to be this one (APK installation file to download):
To follow the evolution of this fork which to date does not have an official web page, consultation of the English-speaking group news.software.readers is recommended.

There is a version of Pan for Windows, but its operation seems unstable. However, it seems that the “Subsystem for Linux” built into Windows 11 can help things along. Read the following tutorial on this subject published on Usenet:
SeaMonkey is a software suite including a web browser (based on Firefox), an HTML editor and email software (based on Thunderbird) which manages both email and news. It has the advantage of accepting old Thunderbird extensions, including Mnenhy which provides some interesting features for reading news.
The official website of the Mnenhy extension having disappeared, here is the last update published:
mnenhy-0.8.6.1.2-stanio.xpi.zip
slrn, born in 1994, stands out for its 'scoring' function allowing messages to be filtered, a functionality which has since been adopted by other newsreaders, such as Pan or Gravity. Configuration is done on the command line.
Like its fork Claws Mail, Sylpheed is both an email software and a newsreader.

The macOS application available for download on the Sylpheed website is based on an old version and cannot be updated. To have the latest version, as well as updates, it is best to install Sylpheed via Homebrew.
Thunderbird is a complete messaging software (mail, RSS and news). For reading news, it allows the choice of 'connected' use (only the article headers are downloaded) or 'offline' use (the full articles are downloaded).
Among the newsreaders still actively maintained today, tin is one of the veterans, since its very first version dates back to 1991. While keeping its interface in text mode (and its command line configuration), it has regularly evolved since then.
Here's a newsreader I thought had disappeared. Thanks to « D », a contributor to the news.software.readers group, for reminding me of its existence.
Among other features, Xnews stands out for its 'scoring' function, explicitly inspired by that of slrn.

While Xnews is perfectly usable by English-speaking users, it will pose a problem in languages requiring non-ASCII characters. To access other character sets, you must associate a small resident software, MIME-Proxy (archive). Read the attached documentation carefully before getting started!
To our knowledge, the Xnews/MIME-Proxy pair cannot manage secure connections. You must therefore stick to port 119.
This document, published on Usenet in 1999 and updated in 2003, lists the features that a good newsreader should have. It is still a reference among developers today.
The original text is now only available in archive form:
GNKSA * The Good Net-Keeping Seal of Approval