StarUML
Commercial
StarUML is an opensource UML tool.
Visual Paradigm
Commercial
Visual Paradigm (VP-UML) is a UML CASE Tool.
Umbrello
Open Source
Umbrello UML Modeller is a free software UML diagram tool available natively for Unix-like platforms and Windows.
Bonita BPM
Open Source
Bonita BPM is an open-source business process management and workflow suite.
Compare Modelio with alternatives
Compare Visual Paradigm and Modelio and decide which is most suitable for you.