PlantUML : PlantUML is an open-source tool allowing users to create UML diagrams from a plain text language
Mermaid : Mermaid is a Javascript based diagramming and charting tool that uses Markdown-inspired text definitions and a renderer to create and modify complex d...
Excalidraw : Virtual whiteboard for sketching hand-drawn like diagrams.
Collaborative and end-to-end encrypted.
Terrastruct is a tool to create diagrams that excel at visually explaining complex systems, such as your organization's engineering architecture.