Ultimate Member - The easiest way to create powerful online communities and beautiful user profiles with WordPress.
MakePlans - Online appointment booking - MakePlans
Paid Memberships Pro - The complete membership solution for your WordPress site.
Appointment Booking Calendar - With the Appointment Booking Calendar you can accept online bookings from a set of available time-slots in the calendar.
WP-Members - WP-Members is a free membership management framework for WordPress that restricts content to...
Dudle - Dudle is an online scheduling application, which is free and open source.