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.
WPAmelia - Award-winning WP booking plugin that manages services, appointments, customers, events, analyze business performance, and accept payments online.
Dotcal - Personalized booking pages for absolutely everyone
Koalendar - Free Online Appointment Scheduling Software
Planist - Schedule meetings in an easy way Planist can connect with your google calendar to automatically check availability and help you connect with your best contacts, prospects, and clients.
Cal.com - Cal.com (formerly Calendso) is the open source Calendly alternative.