Can you remind me how to use all modules in a package?

It all depends on what "all modules in a package" are. I think "all packages in a module" makes more sense...

I thought it was just use Package::*; but that doesn't seem to work.

Why should it? What made you think it would? It's up to Package to provide such functionality. If really needed.

Update: Said this, I can imagine some trickery to "load all modules from Some::Package onwards" (or "downwards"), but I'm not even sure if it can be done reliably and I strongly recommend not to even think of anything like that!