Forms for Metadot Web Portal is a web based forms package for the metadot portal. From your browser you can define a form with checkboxes, radio buttons, etc. Validate minimum length, max size, or against a regexp, attach "help" to field, and usual forms package type stuff. Users can then use the web to enter data according to your forms. It works within the metadot portal environment (nice, flexible portal - gpl mod_perl mysql).
Gaby is a small personal database manager using GTK+ and GNOME (if available) for its GUI. It was designed to provide straight-forward access to the types of databases a casual user would normally use, while keeping the ability to easily create databases for other needs. It was designed with extensibility in mind and relies heavily on plug-ins.
ToutDoux is a project manager for GNOME. The approach of data manipulation is abstract (database free). It's extensible with plugins. Most tasks are and will be subcontracted with commandline frontends. The file format is XML (including a schema, plugins parameters, and datatables).
DbDesigner is a useful tool for constructing databases in an intuitive and easy-to-use environment, where you have a visual representation of the tables and relations contained in your project. You can quickly see the fields in a table or how each table relates to the others. After you are finished, it can export the schema of the database into an .sql script, or directly connect to a database backend and build it there. It can also import already existing databases from .sql scripts or db backends. It can save your project into its native format (XML) so all information is kept, and it has a plugin architecture to be easily extensible to work with many database servers (it comes with 2 plugins for PostgreSQL and MySQL).
LiMpOo is a multimedia player platform based on a Linux system using a Perl engine. It features playback of MP3 files (with playlists), CD audio (with CDDB lookup), and support for encoding, LCD, and IR. It uses MySQL for speed improvements. A PHP front-end helps to maintain all playlists.