[actionowl]

This one is free, we use it and it works for our needs. We also have it integrated with our Active Directory: https://www.verdaccio.org/

[grumblestumble]

We use Verdaccio and I can't imagine any serious dev shop not using some kind of proxy / private registry for NPM packages. It's really simple to set up and has served us well, aside from minor hiccups.