If I want to save a bunch of node groups for later use, is there a better way than just saving them all to a single .blend and making them fake users?
Not that I know of. Maybe as library assets? There might be an addon on the Blender Market that can do something like that, but I wouldn't know either. Here's JL's Ultimate Guide for Addons:
https://cgcookie.com/posts/the-ultimate-2022-guide-to-the-best-blender-add-ons