Evolution is the GNOME mailer, calendar, contact manager, and communications tool. Evolution represents the next step forward in GNOME applications. The tools which make up Evolution will be tightly integrated with one another and act as a seamless personal information-management tool.
fam++ is a C++ wrapper for fam, which uses imon or DNotify (Linux 2.4.x) to inform it when inodes change (the net effect being that applications can register interest in a file, and have events send to the application when the file changes). Fam++ also integrates with gdk and Loki to make creation of C++ GTK+/GNOME apps simpler.
Firestarter is a firewall tool for Linux, and uses GNOME. You can use the wizard to create a basic firewall, then streamline it further using the dynamic rules. You can open and close ports with a few clicks, or stealth your services giving access only to a select few. It features a real-time hit monitor which you can watch as attackers probe your machine for open ports.
Frood is a Gtk/Perl LDAP client designed to work on LDAPv2 and LDAPv3 servers. You can extract data from a server by either searching (either by baseDN, scope, filter, attribute names, or attributes) or by browsing a hierarchial tree structure. Entries can be added, deleted, modified, or have their RDNs modified. LDIF files can be imported and exported. LDAPv3 schema can be edited.