Cronitor - Monitor cron jobs, micro-services, daemons and almost anything else, no setup required. Easier cron troubleshooting and no more silent failures.
Teamup Calendar - Cloud-based calendaring using capability URL, application developed in Zurich, Switzerland.
Trello Calendar Connector by Cronofy - See and Organize your Trello deadlines inside your calendar
Campaign Calendar - Campaign Calendar by Bracket Labs builds a marketing calendar from your Salesforce Campaigns.
Agile Guy for Trello - The Swiss army knife for agile teams!
ApPHP Calendar - ApPHP Calendar is a PHP calendar script that may be easily integrated and used with various PHP projects, such as schedulers, event, etc.