Clocker - Keep track of people in different time zones
Geekbot - Discover how to organise asynchronous stand up meetings in Slack and keep your team synced using Geekbot. Start your free trial today!
World Clock iOS 8 Widget - Check the time, anytime. Just pull down Notification Center.
Chili Piper - Chili Piper is an intelligent calendar for Sales teams, to book their own meetings or set appointments for other teams.
Dato - Better menu bar clock with calendar and time zones
Doodle - Make meetings happen. With Doodle, scheduling becomes quick and easy.