[MrEDaniels]

Are non core supplemental books allowed for gear, vehicles, magic, etc (i.e., Gun Heaven, Used Car Lot, Attitude, War, etc)?

[Critias]

Unless something is called-out as an optional rule, or specifically mentioned as disallowed in the Missions FAQ, it's fair game to use.

[MrEDaniels]

Cool...thanks, I just wanted to be sure that I had it right before I said yes or no (since it only specifically mentions the core books for gear).

[wylie]

I understand War is not allowed at the moment, though a few items are avaible through missions.
Most of the net books, like This Old drone, Gun Heaven, and such are good at the moment, until someone nerfs an ite min them and the devs got to nix the whole book to keep power levels balanced.
Spy Games and such seem ok, at the moment....

[DWC]

That's incorrect.  WAR is most certainly on the table.  The only thing that is completely excluded is Way of the Adept.  Everything else is fully open, aside from the qualities and races explicitly forbidden by the SRM Season 4 FAQ.

[JustADude]

I understand War is not allowed at the moment, though a few items are avaible through missions.

As DWC mentioned, that is inaccurate.

I think you're mistaking some people's massive dislike of War!, resulting in them banning it from Home Games, for an official Catalyst ban from Missions.