MySQL - The world's most popular open source database
Xmind - Xmind is a brainstorming and mind mapping application.
PostgreSQL - PostgreSQL is a powerful, open source object-relational database system.
Visual Understanding Environment - Visual Understanding Environment (VUE) is a mind-mapping and concept-mapping tool.
SQLite - SQLite Home Page
FreeMind - FreeMind is a premier free mind-mapping software written in Java.