Kyber for Slack - All-in-one Slack app: tasks, standups, polls, surveys & more
Appointment Booking Calendar - With the Appointment Booking Calendar you can accept online bookings from a set of available time-slots in the calendar.
Huminos - Free OKR and Growth acceleration platform for Startups
Dudle - Dudle is an online scheduling application, which is free and open source.
Meetingbird - Powerful meeting scheduling and notes — right in your calendar
Pulse 24/7 - Booking & scheduling mobile app for service providers