phpMyAdmin is a tool intended to handle the administration of MySQL over the Web. It can create, rename, and drop databases, create/drop/alter tables, delete/edit/add fields, execute any SQL statement, manage keys on fields, create dumps of tables and databases, export/import CSV data, and administrate one single database and multiple MySQL servers.
GLPI (Gestion Libre de Parc Informatique) is an information resource manager with an administration interface. You can use it to build a database with an inventory for your company (computers, software, printers, etc.). It has functions to make the daily life of the administrators easier, including a job/request tracking system with mail notification and methods to build a database with basic information about your network topology. It provides a precise inventory of all the technical resources (all their characteristics are stored in a database) and management and history of the maintenance actions and the bound procedures. It is dynamic and is directly connected to the users, who can post requests to the technicians.
Ximinez is a disk usage analyzer and comparator. It enables you to take snapshots of disk usage for a given folder, to browse through the snapshots, and to view differences between snapshots. It is aimed towards solving problems like: "Why is my disk suddenly so full when it was OK just recently?" Besides the GUI, the package also includes an optional command line tool, which can be used, for example, in conjunction with a scheduler to take snapshots on a regular basis.