I'm a long-time user of free/open source software, and write various things for both fun and profit. I don't take myself all that seriously and I do all of my own stunts.
You can find me at these fine establishments on the web: Open Source Musings, The Monday Kickoff, Weekly Musings. and The Plain Text Project.
Authored Comments
In the article, all the links to the apps (aside from the links to the source code for each) point to F-Droid. I use LineageOS on my phone and tablet, without Google services so F-Droid is my source of apps.
I don't think that this article was intended to be a comprehensive overview of open source/federated social platforms. Plus, the ones you mentioned have been covered extensively elsewhere. Nothing wrong with devoting a few column inches to lesser-known platforms.