Meetingbird for Gmail - View your calendar and schedule meetings right from Gmail
Frozen Goodies - An advent calendar to get the chance to win daily prizes
Kin Calendar - The simple and connected calendar
25DaysOf - A customizable advent calendar, for everyone
Calendly for Chrome - Schedule meetings without leaving your inbox
Planable.io - Planable is the command center of social media campaigns trusted by agencies, freelancers, and marketing teams, that allows you to easily create, collaborate, get approval and schedule posts for your social media campaigns.