XSDComp (XML Schema compilation)

Open source project to create a XSLT powered W3C XML Schema validator.

GD Graphics Library

GD is an open source code library for the dynamic creation of images by programmers. GD is written in C, and wrappers are available for Perl, PHP and other languages. GD creates PNG, JPEG and GIF images, among other formats. GD is commonly used to generate charts, graphics, thumbnails, and most anything else, on the fly.

OpenSceneGraph

The OpenSceneGraph is an open source high peformance 3D graphics toolkit, used by application developers in fields such as visual simulation, games, virtual reality, scientific visualization and modelling. Written entirely in Standard C++ and OpenGL it runs on all Windows platforms, OSX, GNU/Linux, IRIX, Solaris and FreeBSD operating systems.

Think Pascal 4.5 (Mac)

Pascal development system for the Macintosh.

Lazarus

Lazarus is a free and open source development tool for the FreePascal Compiler (object pascal), which is also free and open source. The Lazarus IDE is a stable and feature rich programming environment (screenshots) for creating self-standing graphical and console applications. It currently runs on Linux, FreeBSD and Win32 and provides a customizable source editor and visual form creation environment along with a package manager, debugger and complete GUI integration with the FreePascal Compiler.

Firebird

Firebird is an OpenSource database environment formerly known as Borland Interbase Version 6. Features include full SQL compliancy, stored procedures, and other advance database features.

Berkeley DB

Berkeley DB is an open-source database system made by Sleepycat Software. It is available in several different distributions including a java beta version. You can use them freely if the the complete source code for your application is available and freely redistributable under reasonable conditions. Otherwise you can purchase a license. See the website for licensing information.

IBM Cloudscape V10.0

IBM Cloudscape V10.0 is a pure, open source-based Java relational database management system that can be embedded in Java programs and used for online transaction processing (OLTP).

db4o

db4o (database for objects) is the open source object database for Java and .NET. It is free software available under the GPL and also under a commercial license. It can persist any native object with a single line of code and allows you to experience true object-orientation. Features include: ACID transactions, query-by-example, S.O.D.A. query API and automatic class schema recognition, small footprint.

Ingres

Ingres is a proven, high-performance open source relational database solution that offers the scalability, integration and flexibility to leverage information resources across a wide range of platforms, including Linux, UNIX, Windows and OpenVMS.