Morgen.so - All-in-one Calendar, Tasks & Scheduler. Morgen is the single hub for everything that revolves around time management.
Lumy - Helps you track photographic times
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.
Sundial App - Sun & Moon times and alerts for iPhone, iPad, & Apple Watch
Calbird - Simple, instant scheduling.
SunCalc - Find out where the sun will be at any time in any location