Modelio - Modelio is an open source modeling tool supporting natively UML, BPMN and model exchange with XMI.
draw.io - Online diagramming application
Diagramo - Diagramo is an online flowchart software - diagrams (create, edit and share)
Visio - Simplify and communicate complex information using data-linked diagrams.
ARIS Express - ARIS Express is based on the proven ARIS methodology and industry standards.
Bizagi Modeler - Business Process Modeling Software. Bizagi BPM software puts simplicity first.