RiddlePortal

RiddlePortal publishes nonogram puzzle books as instant-download PDFs.

Each book is built for the device you'll actually solve it on:

— E-ink editions, laid out at the device's own page size for reMarkable 2, reMarkable Paper Pro and Kindle Scribe, with a tappable index that jumps straight to any puzzle or its solution.
— Print editions, US Letter and A4, with grids sized to fill in by hand.

Every puzzle is checked by a solver before it goes in a book: one solution, reachable by logic alone, no guessing. Full solutions are included at the back of every volume, and volumes are sorted by difficulty.

Nonograms are also known as Picross, Griddlers, Hanjie and Paint by Numbers.

You can get the free demo pages on riddleportal.com