The Living Thing / Notebooks :

Browser data visualisations

General javascript drawing

If you want to do SVGs, snap.js is a modern svg library by the author of raphaƫl.js.

Javascript statistical/mathematical graphing

3D visualisation

Yes, 3D in the browser is performant and convenient. More convenient, than Processing. And you can do 3d dance parties

Two common options use OpenGL ES, the mobile- and browser- friendly option.

Everything supports lense flare.

For desktop apps and a larger OpenGL subset there is a desktop option, Plask which seems to be some kind of particle-system-friendly, OSX app, with spurty development but spectacular potential.

Handy tools

Networks/flowcharts

Weird art toys

p5.js centi.js