There is (the project doesn’t seem to be actively pursued at the moment) a blog series documenting someone‘s journey in procedurally generating fantasy maps. For a while (a bit over a dozen entries from what I could find) he explored map borders which also seem to have some overlap with tiles.

This is the first entry: https://heredragonsabound.blogspot.com/2019/02/map-borders-p...

Edit: here‘s an interesting post about Celtic knots:

https://heredragonsabound.blogspot.com/2019/05/map-borders-p...