Awesome Cal - Awesome Cal is a Calendar application for your iPhone that you can take anywhere and keep close by to monitor all the upcoming birthdays, festivities, meetings, and more from a single place.

Google Contacts - Google Contacts is Google's contact management tool that is available in its free email service Gmail, as a standalone service, and as a part of Google's business-oriented suite of web apps Google Apps.

Fantastical 2 - Fantastical, the Mac calendar app you'll enjoy using. Quickly create new events with natural language input and more.

Apple Contacts App - Access and edit your contacts from personal, business, and other accounts with the Contacts app.

Pocket Informant - Pocket Informant is the Best Calendar app for mac and iOS. Pocket Informant for iOS, Mac desktop, and Android.

Windows Contacts - Windows has many extraordinary organizers, and in the event that you include distributed storage, then you presumably have more.