A Database System for Metamodeling and Method Engineering
The Umple Model-Oriented Programming Technology
Syntax tree editor for rapid annotation of existing text
Open-source code generator for Simulink/Stateflow
A free cross-platform editor for the DRAKON visual language.
A PlantUML editor written in Qt4
Code generation from UML to any language (Java, Objective-C, PHP...)
Visualize Galois sub-hierarchy of 2d matrix