I noticed "The Ultimate FOSS Guide for Android" was very out of date and thought I'd try to make a new version with more current suggestions. But after a while I realized most of the time I was just copying off PrivacyGuides.org which has a pretty robust set of FOSS offerings with an unsurprising focus on privacy.
There are still some things it doesn't cover like Android launchers and keyboards, but we could have an additional sidebar post with more a la carte suggestions.
Thoughts? 
Third party launchers and keyboards can be a security risk and its best to use the bundled ones.
No comment on launchers, but a FOSS keyboard is way less of a security risk than your bundled one that is 100% spying on you.
Foss keyboard, and also the keyboard should never need network access.
Well I just assume a privacy post would involve using a ROM that doesn't have a keyboard that does that.
People running privacy centric custom Android ROMs are way past needing privacyguides.org software recommendations.
Unless of course it's FUTO keyboard :)
Source available for analysis is a big deal.
openboard or heliboard are FOSS and good on that front. they fork gboard and behave similarly.
trebuchet is available on the play store iirc and is good toono its not