PCI Express 6 pin-Female to 8 pin-Male Power Adapter Cable - Micro Connectors, Inc.
Segotep 6 Pin to 2 X 8 Pin (6+2) PCIe Adapter Power Cable PCI Express Y-Splitter Extension Cable 9 Inches 6 Pack - Newegg.com
PCI Express 6 pin-Female to 8 pin-Male Power Adapter Cable - Micro Connectors, Inc.
Amazon.com: StarTech.com 6in SATA Power to 6 Pin PCI Express Video Card Power Cable Adapter - SATA to 6 pin PCIe power, Black, Yellow (SATPCIEXADAP) : Electronics
Amazon.com: StarTech.com 6in LP4 to 6 Pin PCI Express Video Card Power Cable Adapter - Power adapter - 4 pin internal power (M) to 6 pin PCIe power (M) - 6 in - LP4PCIEXADAP : Electronics