I remember some years ago seeing a youtube video of a sketching software that worked like a full screen overlay. It was also featuring an unlimited canvas.
The sketching tools were quite basic but more advanced than those annotation apps.
Anybody knows what I saw? I cannot find it anymore.
Epic Pen creates an overlay that lets you to draw, write and highlight over any desktop software in real-time, allowing you to move seamlessly between your software and your notes.
Like I said, it might not be the one you are thinking of…but does what you requested…it’s FREE …Try it and see!