Somehow, many more half-height PC cases were released in recent years, and I wonder why, when people can't find proper components for them. The same with some cases that support Flex-ATX PSUs or weird non-standard PSUs. Those are mainly from lesser-known Chinese brands, but in Asia, they sell quite well.
There were single half-height graphics cards with a power connector, but I don't remember what they were. They were still lower GPUs at ~100W. When I was testing some of the new graphics cards, I noticed they barely use the PCIe slot to deliver power. Almost everything they take from the power connector on top of the card. Half-height could still have it on the side, but there will still be a problem with cooling.
For some reason, new 300mm, 2-slot, and not too tall cards are now called SFF versions. I saw many negative comments on the web about it, as it's hard to call it SFF, but all leading brands and Nvidia are pushing this idea. In the end, you make an ITX PC that is 30% smaller than a typical large mid-tower. This is why Corsair 2000D or the latest Fractal ITX cases don't sell. They are ITX, but take almost as much space as a typical large tower.