Koalendar - Free Online Appointment Scheduling Software
FullCalendar - FullCalendar is an open-source JavaScript event calendar.
Acuity Scheduling - Automate your client bookings, cancellations, reminders & payments using the worlds friendliest online scheduling software.
Letsfind - Letsfind is a fast, easy-to-use, ad-free way to create online (meeting) polls.
Trafft - An online scheduling software that provide support to any business that relay on bookings.
CozyCal - Online appointment scheduling