Appointment Booking Calendar - With the Appointment Booking Calendar you can accept online bookings from a set of available time-slots in the calendar.

Chili Piper - Chili Piper is an intelligent calendar for Sales teams, to book their own meetings or set appointments for other teams.

MakePlans - Online appointment booking - MakePlans

Geekbot - Discover how to organise asynchronous stand up meetings in Slack and keep your team synced using Geekbot. Start your free trial today!

Dudle - Dudle is an online scheduling application, which is free and open source.

Doodle - Make meetings happen. With Doodle, scheduling becomes quick and easy.