My dad had an interesting selection
Castrol GTX conventional and M1 synthetic.
He bought Castrol GTX during the 70s and 80s because it was advertised as "The oil for smaller, harder working engines" and he had a 1971 Toyota Corolla, 1979 Toyota Corolla, and 1987 Hyundai Excel so those engines were worked hard every day. He said that he used 20w50 Castrol GTX in the Hyundai Excel, and when he traded it in, the salesmen had to show the odometer readout to everybody who worked at the dealer. Nobody had even seen a Hyundai Excel go that far.