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

AnkiDroid: Anki flashcards on Android. Your secret trick to achieve superhuman information retention.

Static code analysis for Kotlin

A simple, rational music player for android

ConnectBot is the first SSH client for Android.

Minimalistic audiobook player

An Android app that uses your phone's sensors to assist with wilderness treks or survival situations.

DAVx⁵ is an open-source CalDAV/CardDAV suite and sync app for Android. You can also access your online files (WebDAV) with it.

Open-source weight and body metrics tracker, with support for Bluetooth scales

A simple calendar with events, customizable widgets and no ads.

🎉 A beautiful Kotlin app to remember birthdays and events without having to open Facebook, set alarms or rely on Google Calendar

Android app for ntfy.sh

jtx Board allows you to manage your Journals (like meeting minutes), Notes and Tasks in one Android app. The app is compatible with the iCal standard (RFC5545) and is integrated with DAVx5 to allow…

ICSx⁵ is an Android app to subscribe to remote or local iCalendar files (like time tables of your school/university or event files of your sports team).

A Sync Browser: a browser app for Syncthing-compatible shares