Donte The Calendar - Send calendar invites using phone numbers
Meetingbird for Gmail - View your calendar and schedule meetings right from Gmail
Planyway - Visual project management for Jira and Trello: manage resources, build project roadmaps, use time tracking.
Kin Calendar - The simple and connected calendar
Calendar Screener - Rules to manage your calendar invites.
Calendly for Chrome - Schedule meetings without leaving your inbox