comlain - A work tracking system.

PTS - is a problem tracking package based around X and the Athena widgets

RUST - Problem/Work tracking package which can handle multiple mailing lists.

TRS2 - Trouble Report System - This is a set of Bourne shell scrips and C programs intended to maintain a database of trouble reports.

The Wesleyan Student Net - RT is a request tracking package based on the "user sends mail to a group of people to report a problem which is then tracked and dealt with" paradigm. RT is written in perl5 with a mySQL backend and has CLI and Web interfaces. It's free.

WebTTS - WebTTS - A WWW-based trouble ticketing system written in Perl 5 and designed with ease of use and an Internet-oriented environment in mind, with a backend that uses MySQL.