Molly - a signal fork with a fully Foss option
Molly is an independent Signal fork for Android.
Molly (Signal fork)
Molly - a better signal
Molly messager - a signal fork focused on security and freedom. It is available on F-droid though a repo
I was so glad to have found this after reading Drew DeVault's I don't trust Signal blog post from 2018. Only other alternative I found was Signal-FOSS.