MDG for Sparx' Enterprise Architect to Create TRAK arch. descriptions
an Open Source BPMN 2.0 / DMN 1.1 Modeler
A canvas library for generating technical drawings
A free cross-platform editor for the DRAKON visual language.
A modeling tool for software engineers (OO)
Prototype editor for the SDEM Mapping Language
Uses GraphViz to draw UML class diagrams