Diagram Designer is a vector graphics editor that allows you to create UML class diagrams, illustrations, flowcharts and slide shows. Developed by Meesoft
License: Free
Diagram Designer is a user-friendly GUI tool suitable for a variety of diagram types, making it ideal for users who prefer visual design. In contrast, PlantUML is a text-based tool that excels in creating UML diagrams and is favored for its quick edits and integration capabilities, though it requires more technical know-how.