Kontact

Kontact is the integrated Personal Information Manager of KDE.

Alpine

Alpine is a fast, easy to use email client that is suitable for both the inexperienced email user…

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

There’s big news attached.

Features | 1.0.175 for Android™

Contact sync application.

Material design open source calendar for Android.

Apps/Evolution - GNOME Wiki!

Put the power of full contact information into your web or mobile apps.

GNOME Calendar is a simple and beautiful calendar application designed to perfectly fit the GNOME…

Spend less time managing your day & more time enjoying it

KAddressBook stores all the personal details of your family, friends and other contacts.

Organize your life — it’s about time!

Memotoo allows you to sync your data (contacts, calendar, tasks, .) with phones (iPhone, Android, Samsung, ..

Add forums and commenting to your site. Unlimited posts, users and traffic, for free. Embeddable, styleable and scriptable.

Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.

Rainlendar - Customizable desktop calendar

A simple calendar with events (optional recurring and reminders), week numbers and a customizable…

Take control of your schedule and get reminded wherever and however you want.

eM Client is a Windows-based email client for sending and receiving emails, and managing calendars, contacts and tasks.

Free service that takes care of your contacts, calendars and more so you don’t have to.