ASUS has a tour of their HQ during their Computex 2023 showcase and they showed off an ROG graphics card based on the NVIDIA GeForce RTX 4070, which actually does not have any standard power connections at all. It not only gets power from the PCI-Express slot in the motherboard, but also a proprietary slot.
This card is still in the concept phase. As I said it is going to get power from the PCI-Express slot, but at the bottom of the card there is also a special PCIe like slot connector which delivers power to the card. This special connector needs a special slot on the motherboard and ASUS also had a special motherboard on display that features this slot.
This TUF Gaming branded board features a design that has all of the connectors on the back of the board. These connections include your standard power and other connectors like SATA ports, but there are also three 8-pin PCI-Express and a single 12VHPWR connector, which are meant to power the graphics card. With the connections on the back of the board you will also need a special case to support this motherboard.
As of right now ASUS is currently limiting the motherboard design to 600W to accommodate the GeForce RTX 4070, but there could possibly be plans for a RTX 4090 model. According to the report this combo (motherboard + graphics card) could be made available globally as a limited edition as ASUS tests the market and demand for these type of products.