Simple Fullscreen Clock Screensaver
- analog and digital clock can be activated or deactivated individually
- optional date and weekday view with custom format option
- displays alarms and appointments from Android calendar or internal event database
- adjustable background and clock color
- can be set as Android system screensaver ("DayDream") on smartphones and tablets
- compatible with Android TV devices
- content can be moved slightly to prevent burn-in on OLED displays

This app is Open Source:
https://github.com/schorschii/FsClock-Android