The FTP server of the computer science department at Technische Universität Berlin always had an extensive Atari section with freeware, shareware and public domain software. Sadly, some time ago the server was taken offline without any notice, when their IT was restructured. I feared that all content had been lost forever.
However with a lot of effort I was able to obtain a snapshot of the Atari folder on that server from 2015. Since no one volunteered to put it online, I decided to host it myself. So, from now on you can find ca. 400 MB of Atari software at http://atariftp.czietz.de/pub/atari/
Some of the software is in German, some of it in English. The index files are mostly English, though, so you can see what you'll find there.
A request: If you decide that you want the whole collection, please do not put a download manager to work to download all the files. Send me a PM and I'll give you a temporary link to download everything in one file.