BiRT - Business Intelligence Reporting ToolWith BIRT you can create data visualizations, dashboards and reports that can be embedded into web applications and rich clients.
VTK - The Visualization Toolkitis open source software for manipulating and displaying scientific data. It comes with state-of-the-art tools for 3D rendering, a suite of widgets for 3D interaction, and extensive 2D plotting capability.
Kroki provides a unified API with support for BlockDiag (BlockDiag, SeqDiag, ActDiag, NwDiag, PacketDiag, RackDiag), BPMN, Bytefield, C4 (with PlantUML), Ditaa, Erd, Excalidraw, GraphViz, Mermaid, Nomnoml, Pikchr, PlantUML, Structurizr, SvgBob, UMLet, Vega, Vega-Lite, WaveDrom... and more to come!