PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.
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.
Modelio is an open source modeling tool supporting natively UML, BPMN and model exchange with XMI.
UMLet - Free UML Tool for Fast UML Diagrams
Looking for an affordable software with Enterprise Architecture tool, PMBOK tool, UML tool, Agile tool, BPMN tool and UX tool? Read this page for details.
Online diagramming application
Lightweight, powerful, easy to use, UML tool
€59.0 / One-off (Standard Edition)
Umbrello UML Modeller is a Unified Modelling Language diagram programme for KDE.
Enterprise Architect - UML Design Tools and UML CASE tools for software development | Sparx Systems
Dia is a GTK+ based diagram creation program for GNU/Linux, MacOS X, Unix, and Windows, and is released under the GPL license.