Things I've built. Mostly open-source. Some in production, some experiments.
Animations run outside the React render path: the orchestrator drives them through WAAPI and requestAnimationFrame, and only touches composited properties, so a running animation does not trigger layout. Built mainly to understand where the cost in existing animation libraries actually comes from.
Route params, search params, and navigation are typed from a single route definition using template literal types, so the types cannot drift from the routes. What ships at runtime is a small matcher; the rest is erased at build time.
Nodes render in WebGL through a custom render loop, while text and inputs stay as DOM overlays positioned from the same transform. Zoom and pan run on the GPU, which keeps the canvas responsive as the node count grows.