Cronitor - Monitor cron jobs, micro-services, daemons and almost anything else, no setup required. Easier cron troubleshooting and no more silent failures.

incron - This program is an "inotify cron" system. It consists of a daemon and a table manipulator.

Trello Calendar Connector by Cronofy - See and Organize your Trello deadlines inside your calendar

fcron - Fcron is a scheduler designed for Unix/Linux systems, especially usefull when your system is not up all the day long.

Agile Guy for Trello - The Swiss army knife for agile teams!

Anacron - Anacron is a periodic command scheduler. It executes commands at intervals specified in days.