Interesting that in the USA there are still so many different grades of gasoline sold.
I can remember until the mid 1980s in the UK they used to sell (leaded)
2-star, 3*, 4* and 5* (different octane ratings for cars with different compression ratios). But then when new cars started to be made with engines that took unleaded petrol and had catalytic converters (which happened much later with us than I believe it did in the States) and high-compression engines were phased out, they went over to just unleaded and leaded, each in regular and premium.I don't think any garages sell leaded now, since most engines can be converted and the small number of older ones that can't can use an additive to each tank of unleaded.
Nowadays almost all pumps on a garage forecourt just sell unleaded (green holster) and diesel (black or blue holster), with maybe one or two pumps also having a nozzle for premium unleaded.
One or two brands of fuel (I think BP - British Petroleum - is one of the few) also have a pump selling premium diesel - at a "gold-plated" premium price!
I've not heard any suggestions yet that we might gradually change over to gasoline with some ethanol in. Even bio-diesel hasn't really taken off over here, though I've heard of a few people running cars on recycled cooking oil - which, to be legal, should have tax paid on it when it is put into a car...