e.g. something like this so if you haven't played in a while you can just look at it to get the pattern / route back into your mind. or for new players who can't remember it all yet.

A Pokemon picross guide dues exist here https://apps.keeky.net/pokemon/picross/ but it isn't the most useful during multi level speedruns as you would have to keep changing the level on the website

Sorry for responding so late, but I've been using the site pikachu listed, screenshotting all of them, and putting them on a google doc for any%.