A little while ago, I played around with TikZ to make printable paper. As it turns out, this is absolutely trivial, and with just a few lines you can generate pretty much anything you can imagine. Here are the examples that I generated:
A4 paper
Blank Paper
Ruled Paper
Graph Paper
- Lin 22 5mm graph paper, no margins (TeX)
- Lin 23 5x9mm graph paper, no margins (TeX)
- Lin 26 5mm graph paper with right margin (TeX)
- Lin 28 5mm graph paper with two margins (TeX)
- Millimeter graph paper (TeX)
Underlay Paper
- Lin 22 5mm underlay, no margins (TeX)
- Lin 28 5mm underlay with two margins (TeX)
- Personal Correspondence (TeX)
Letter size paper
Cornell Paper
- Cornell blank note taking paper (TeX)
- Cornell college ruled note taking paper (TeX)
- Cornell ¼ inch graph note taking paper (TeX)
Ruled Paper
Graph Paper
Underlay Paper
You can adapt any of these examples to your needs easily, as well as create more complicated layouts. Anything you can find on http://www.printablepaper.net/, for sure. To compile, run the tex file through pdflatex twice.
Goodnotes
Moving beyond "printable" paper to "virtual" paper, the Goodnotes app allows to define custom templates. The following template was created so that for a fully zoomed out letter-sized page on a 13 inch iPad Pro screen, the grid is exactly 5x5 mm on screen. This way, I can use a physical ruler on top of the iPad screen.