Xmind - Xmind is a brainstorming and mind mapping application.
Diagramo - Diagramo is an online flowchart software - diagrams (create, edit and share)
Visual Understanding Environment - Visual Understanding Environment (VUE) is a mind-mapping and concept-mapping tool.
Modelio - Modelio is an open source modeling tool supporting natively UML, BPMN and model exchange with XMI.
FreeMind - FreeMind is a premier free mind-mapping software written in Java.
UML Designer - UML Designer provides a set of common diagrams to work with UML 2.5 models.