Allume
Allume, formerly Muse, is a local-first visual thinking app for Mac, iPad and iPhone. It helps develop research, designs, stories and plans without forcing ideas into a linear document.
Scrintal
Visual note-taking on an infinite canvas, linking notes as cards.
tldraw
tldraw is a React and TypeScript SDK for building infinite-canvas applications, from collaborative whiteboards and diagrams to custom visual editors.