Lightning
Open Source
Lightning App Builder is a point-and-click tool that makes it easy to create custom pages for Salesforce1 and Lightning Experience.
fruux
Freemium
fruux is a cross-platform synchronization service.
Rainlendar
Freemium
Rainlendar is a calendar program for Windows, Mac OS X and Linux.
BusyCal
Commercial
BusyCal is a calendar app for mac.
Compare Google Calendar with alternatives
Compare Lightning and Google Calendar and decide which is most suitable for you.
Compare Rainlendar and Google Calendar and decide which is most suitable for you.
Compare fruux and Google Calendar and decide which is most suitable for you.
Compare BusyCal and Google Calendar and decide which is most suitable for you.