Doodle - Make meetings happen. With Doodle, scheduling becomes quick and easy.
Letsfind - Letsfind is a fast, easy-to-use, ad-free way to create online (meeting) polls.
DFN Scheduler - Easy and fast coordination of appointments that pays special attention to the protection of data on the one hand, and the data economy on the other not choosing to provide additional features. All data used are exclusively stored in Germany.
CozyCal - Online appointment scheduling
When2Meet - When2meet helps you find the best time for a group to get together. It is a free survey tool that is quick and easy to use.
FullCalendar - FullCalendar is an open-source JavaScript event calendar.