SyncThemCalendars allows you to synchronize calendars across Google accounts
Calendly - Say goodbye to phone and email tag for finding the perfect meeting time with Calendly. It's 100% free, super easy to use and you'll love our customer service.
Motion Firefox - All-in-one time management tool in Firefox
OneCal.io - Sync Outlook and Google Calendars in real-time, share booking links, and view all your calendars in one view.
Taskable - Using multiple work apps leads to tons of context switching, breaking flow and killing productivity.
Acuity Scheduling - Automate your client bookings, cancellations, reminders & payments using the worlds friendliest online scheduling software.
Task Muncher - Task Muncher is a cross-platform and web-based application that is designed to organize and keep the track of everything and focus on munching the weekly tasks.