Berkeley Mailbox (.mbox or no extension):

The email format used by Mozilla, Netscape, Evolution (for local folders until version 2.32), Eudora, and many other email clients.

Maildir (no extension):

The format used by Evolution (for local folders since version 3.0). There is no need to import Maildir files as you can configure a Maildir account in Evolution and point to the folder where the Maildir files are stored.

Outlook Express 5/6 Personal Folders (.dbx):

The email file format used by Microsoft Outlook Express 5/6. For newer versions PST import is recommended.

vCalendar (.vcs):

A format for storing calendar files, which is generally used by Evolution, Microsoft Outlook, Sunbird, and Korganizer.

iCalendar or iCal (.ics):

A format for storing calendar files. iCalendar is used by Evolution, Microsoft Outlook, Palm OS handhelds, and others.

LDAP Data Interchange Format (.ldif):

A standard data format for contact cards.

vCard (.vcf, .gcrd):

The address book format used by the GNOME, KDE, and many other contact management applications. You should be able to export to vCard format from any address book application.

Evolution/Mozilla/Outlook CSV/Tab (.csv, .tab):

CSV (Comma-separated values) or Tabulator files saved by using Evolution, Microsoft Outlook and Mozilla.

Outlook Personal Folders (.pst):

A file format used to store local copies of messages, calendar events, and other items within Microsoft software such as Microsoft Exchange Client, Windows Messaging, and Microsoft Outlook. It is also called "Personal Storage Table".