Modelio - Modelio is an open source modeling tool supporting natively UML, BPMN and model exchange with XMI.
LucidChart - LucidChart is the missing link in online productivity suites. LucidChart allows users to create, collaborate on, and publish attractive flowcharts and other diagrams from a web browser.
Diagramo - Diagramo is an online flowchart software - diagrams (create, edit and share)
draw.io - Online diagramming application
ARIS Express - ARIS Express is based on the proven ARIS methodology and industry standards.
Visio - Simplify and communicate complex information using data-linked diagrams.