Trello Calendar Connector by Cronofy - See and Organize your Trello deadlines inside your calendar
Google Calendar - Spend less time managing your day & more time enjoying it
Bringschuld - Simple periodic task and email monitoring
CalenGoo - Features | 1.0.175 for Android™
Cronitor - Monitor cron jobs, micro-services, daemons and almost anything else, no setup required. Easier cron troubleshooting and no more silent failures.
Jorte - Schedule books must be practical and has a good design.