Simple Calendar - A simple calendar with events (optional recurring and reminders), week numbers and a customizable...
Morgen.so - All-in-one Calendar, Tasks & Scheduler. Morgen is the single hub for everything that revolves around time management.
Etar - Material design open source calendar for Android.
Zoho Calendar - Zoho Calendar is a business calendar that comes along with the Zoho Mail suite of applications. Make your schedules click by effortlessly managing events with Zoho Calendar.
Google Calendar - Spend less time managing your day & more time enjoying it
Calbird - Simple, instant scheduling.