What are the part numbers for PCI-E 8-pin and 6-pin power connectors?
The 6-pin versions are:


45558-0003 - (*) Molex Mini-Fit JR, PCIe Applications, Right-Angle, 6-pin Header 
45718-0002 - Molex Mini-Fit JR, PCIe Applications, Vertical, 6-pin Header
45559-0002 - Molex Mini-Fit JR, PCIe Applications, 6-pin Receptacle


The 8-pin versions are:


45586-0005 - Molex Mini-Fit JR, PCIe Applications, Right-Angle, 8-pin Header  with polarisation link. 
Vertical header part numbers unknown.
45587-0004 - Molex Mini-Fit JR, PCIe Applications, 8-pin Receptacle with polarisation link.




(*) The original part number was 45558-0002 part has been superseded by 45558-0003.