Meetingbird for Gmail - View your calendar and schedule meetings right from Gmail
Clara - Clara is a virtual employee that schedules your meetings, getting you to the work that matters, faster.
Kin Calendar - The simple and connected calendar
MeetFox - Seamless meetings, online scheduling, video calls & payments
Calendly for Chrome - Schedule meetings without leaving your inbox
Busy Zone - Have you ever tried to agree on meetup date and time with several people?