Modelio - Modelio is an open source modeling tool supporting natively UML, BPMN and model exchange with XMI.
Sketch - Professional digital design for Mac.
Diagramo - Diagramo is an online flowchart software - diagrams (create, edit and share)
Inkscape - Inkscape is a free, open source professional vector graphics editor for Windows, Mac OS X and Linux.
ARIS Express - ARIS Express is based on the proven ARIS methodology and industry standards.
Affinity Designer - Professional creative software, exclusively for Mac.