Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

An F-Droid client with modern UI and an arsenal of extra features.

Jitsi Videobridge is a WebRTC compatible video router or SFU that lets build highly scalable video conferencing infrastructure (i.e., up to hundreds of conferences per server).

Android application compatible with ZX2C4's Pass command line application

A lightweight Android browser with modern navigation

A small, fast web browser based on Android WebView. It's tailored for E-Ink devices but also works great on normal android devices.

FFUpdater: Updater for privacy friendly browser

⏲ A highly customizable interval timer app for Android

Android app client for Shiori