The nixpkgs-unstable channel's programs.sqlite was used to identify packages producing exactly one binary, and these automatically added to their package definitions wherever possible.
Adding palapeli because I couldn't find a jigsaw puzzle game in nixpkgs. Didn't find that anyone on [Reddit](https://www.reddit.com/r/NixOS/comments/yf7h2e/any_packages_for_jigsaw_puzzle_apps/) knew of one, either. Behold, palapeli in nixpkgs!