Cron - Cron Calendar.
Deepnote - A collaboration platform for data scientists
Cal.com - Cal.com (formerly Calendso) is the open source Calendly alternative.
Gyana - Intuitive easy-to-use report and dashboard tool to stop wasting time on repetitive and tedious tasks.
zcal - zcal is the fastest way to schedule every meeting for Free and make it personal.
DataQuest Beta - Codecademy for Data Science