Thought I would comment since I noticed the "potentially trivial works" tag. I think this has a lot of potential, I'm always on the lookout for handdrawn assets on the site (especially decent-looking UI!). I think it would be fun to put together some sketchy kind of game at some point.

That being said, this would have a lot more utility without the contrast and brightness edits. Also, having a version with and without the graph lines would be super. It may not be worth it for you to do any of that, but I thought the feedback may be helpful.

Yes, the 'potential triviality' in this case is less about "could easily be reproduced by the average person in a few minutes" and more about "the asset would not save the downloader very much time". There are certainly more than a few minutes worth of sketches in the download, but nearly all of them would require an excessive amount of image processing to get them to a usable state. Nearly all scans-of-drawings-on-paper don't really get a lot of use on OGA because they take so much time editing out the paper background and, in this case, graph lines. I am welcome to be wrong, and if there is a version with better contrast and less graph lines, it would not quality as "trivial"