an Open Source BPMN 2.0 / DMN 1.1 Modeler
E-XD++ Diagram Control for C/C++, .NET, the professional Diagram.
E-XD++ UML Control for C/C++, C# and .NET, it can be used within Delph
Jade is a cross-platform diagram editor built on the Qt framework.
Visio style source code component library, flow charts, vector