Simple cable combs that holds them at a 90° angle. The key clips in to prevent the cables from pulling out and to keep them pushed in all the way. I recommend using a softer filament like Polymaker PolyTerra for the added flex so it's easier to remove the key if needed.

Sizes include:
24-pin (Motherboard 24-pin or 8+8+8 PCIe)
22-pin (8+8+6 PCIe)
16-pin (8+8 PCIe)
14-pin (8+6 PCIe)
12-pin (8+4 EPS or 6+6 PCIe)
8-pin
6-pin
4-pin (CPU)