Appointment Booking Calendar - With the Appointment Booking Calendar you can accept online bookings from a set of available time-slots in the calendar.
Charitable - A WordPress donation plugin that gives you full control over your fundraising experience.
Dudle - Dudle is an online scheduling application, which is free and open source.
Give - A WordPress plugin for easily collecting donations
MakePlans - Online appointment booking - MakePlans
GiveForms - Your Go-to Digital Fundraising Platform