So 19494 is the largest? That's far lower than I expected. There's nobody out there that has put a date in a version number (e.g., 20250915)?

There are plenty of larger ones and plenty of ones that used the date as the version, but I was mainly curious about packages that followed semver.

Any package version that didn't follow the x.y.z format was excluded, and any package that had less published versions than their largest version number was excluded (e.g. a package at version 1.123.0 should have at least 123 published versions)

Well, we are looking at npm packages, where every package is supposed to follow semantic versioning. The fact that we don't have date as version number means everyone is a good citizen.

https://docs.npmjs.com/about-semantic-versioning