Cal.com - Cal.com (formerly Calendso) is the open source Calendly alternative.
Calendly - Say goodbye to phone and email tag for finding the perfect meeting time with Calendly. It's 100% free, super easy to use and you'll love our customer service.
WhenWorks - Mobile appointment scheduling
Acuity Scheduling - Automate your client bookings, cancellations, reminders & payments using the worlds friendliest online scheduling software.
Inspora - virtual chat-stylist for fashion advice.
Doodle - Make meetings happen. With Doodle, scheduling becomes quick and easy.