The Zimlet gallery is the best place to find and publish extensions for Zimbra.
Zeta Alliance - Zimlets
Zimbra ownCloud Extension Zimlet
Dir Antichat, PDF, My Sql
Zimbra Collaboration Administrator Guide
Zeta Alliance - Photos And Files?sort=newest Zimlets
WebDAV - Zimbra :: Tech Center
Subdomains Top1million 5000, PDF, Computing
Zeta Alliance - Zimbra WebDAV Client
Dir Antichat, PDF, My Sql
Zeta Alliance - Users
Zimbra and Seafile: the New Collaboration Dream Team – Seafile