Back when we had to use the Source SDK tool to open Hammer, the install of it included a bunch of official vmf files (non-decompiled!) for a bunch of maps. Since Source SDK is no longer required, and it seems like they aren't included in that install anymore anyway, here they all are!
Files included in this zip file:
Note that these are not necessarily the latest versions of these maps, so things might be a little different from current stock. These are intended to be for educational use. I obviously hold no rights to these, they are 100% Valve products, I'm just sharing them for ease of use.