StylusLabs Write. I've tried all the FOSS hand-written note taking apps and none of them is practical to use.
Write just works. Produces SVGs that you can view in any browser and efficiently sync via git. Amazing.
It looks like an android app from 2012 and could really use some updates in other areas too.
I also don't get why it's closed source. It's free (as in beer) and there isn't even a way to donate.
Back when I tried it, there was basically no ability to, like, copy paste, clone, move, delete or otherwise modify existing strokes. I believe it also had no infinite canvas?
Could also be that I was either too stupid for the UI, I didn't take a look at it for very long.