Modelio : Modelio is an open source modeling environment (UML2, BPMN2, ...). Based on a 20-year track record of high end commercial products, Modelio delivers a...
iPlotz : Wireframing, mockups and prototyping for websites and applications
Leaflet : A Modern, Lightweight Open-Source JavaScript Library for Interactive Maps
Origami Studio : Origami is a free tool for designing modern user interfaces.
