Let's see, from the current FCA, only the real Italian brands I've not been in. I've driven Jeep, Dodge, Chrysler, Plymouth and RAM. Maybe not an Eagle, but certainly an AMC if you count them as part of the MOPAR family back in the day.
GM - pretty much everything. Chevy and GMC, Buick, Olds, Pontiac, Cadillac, Hummer if you count the military. Holden if you count a rebadged Commodore here as a GTO. Even a Saturn. Probably not an Opel as much as I'd like to have a go at the poor man's Corvette. Am I missing anything in this family?
Ford - Ford, Lincoln, Mercury. But none of the stuff that was part of Ford when they had a bunch of prestige brands like Aston Martin, etc.
Germany - been in the common US imports, VW, BMW, Mercedes and Audi
Korean - Both Kia and Hyundai have been a ride.
Japanese - Honda, Toyota, Subaru, Isuzu, Mazda and Mitsubishi have all carried me somewhere, am I missing anything here, probably been in all of the up-market brands like Acura, Lexus and Infinity as well. Probably as Suzuki, but it may have been a GM, and certainly I've ridden a Suzuki Motorcycle, so I'm going to count it as one I've had as transportation.
If anything French or Italian, I don't recall.
I think the only thing British was my former stepfather's Morris Minor back in the late 1960s.