OpenDD is a DynDNS client, written in C, and especially designed for small gateway machines, like a Soekris box. Its main feature is that it does not require any Perl or Python interpreter. It supports HTTPS, can send a mail report, and can run as daemon. It is also very easy to deploy.
ZoneAdmin is a Web interface for the powerDNS name server using the MySQL backend. It allows you to manage existing zones and add, remove, and alter new ones, supports on-the-fly input validation, and allows comments per zone and per record. Furthermore, it keeps a detailed history of changes and allows you to temporary enable or disable zones without having to remove them completely. New zones can use templates that contain predefined records. It is designed to be used with one of Apache's authentication methods.
RIR to DNS converter is a tool to convert Regional Internet Registry data to a DNS country lookup zone. You can use it to build your own DNS zone for looking up country codes from IP addresses. It uses data directly from RIPE, ARIN, APNIC, LACNIC, and AFRINIC. The data can be updated on a schedule of your choosing.
Zoned manages BerkeleyDB zone databases using the BDB Replication Base API. It manages all node communication and eases the difficulties that BerkeleyDB replication imposes (such as making sure that all zone changes go straight to the master node for transaction processing). It requires the BIND9 DLZ BDBHPT driver.