"Aubit 4GL" is a project to make GPL, OpenSource, Informix-4GL compatible compiler, and continue to extend functionality needed to write most efficient and productive business related, database oriented applications. See "Home Page" link for more.
oraToolKit is the Swiss Army Knife for Oracle. Standards and well designed tools help DBA's mastering Oracle 10g / 11g throughout the whole lifecycle. OTK runs on Linux, zLinux, Solaris, AIX, HP-UX and other UNIX based systems.
db4o is the world's leading open source object database for Java and .NET. Leverage fast native object persistence, ACID transactions, query-by-example, S.O.D.A object query API, automatic class schema evolution, small size (http://developer.db4o.com)