Cronitor - Monitor cron jobs, micro-services, daemons and almost anything else, no setup required. Easier cron troubleshooting and no more silent failures.
PortKnox - PortKnox is a free OwnCloud provider.
Dead Man's Snitch - Monitor Cron Jobs and Windows Scheduled Tasks with ease.
cloudlay - Cloudlay is a commercial OwnCloud provider
Cronhub - Cronhub helps you to easily monitor all your cron jobs in a beautiful dashboard. It alerts you when your cron job doesn't run on time or it fails.
1.1.1.1 - The free app that makes your Internet safer.