Cvent - Cvent's event management software provides event planners with a complete solution to increase event attendance and decrease event costs.
Cal.com - Cal.com (formerly Calendso) is the open source Calendly alternative.
Eventzilla - Eventzilla lets you sell tickets online and manage attendees from one integrated application.
WhenWorks - Mobile appointment scheduling
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Inspora - virtual chat-stylist for fashion advice.