Features:
- Month view.
- Week, day and agenda view.
- Uses Android calendar sync. Works with Google Calendar, Exchange, etc.
- Material Design.
- Dark and light theme.
- Free, open source and absolutely no ads.
- Support sharing calendars via ICS and the ability to import/export from SD card.
- Multilingual UI.

Bugs and feedback: https://github.com/Etar-Group/Etar-Calendar/issues
Source code: https://github.com/Etar-Group/Etar-Calendar