PSU > 800GY / 0800GY (eBay)(search 800GY or Alienware 1500)

Cable Part #'s (*for 'older' R2) > 1ˢᵗ set TMR06 / 2nd HPDD5 / 3rd JPV3Y

*R3 - R8 part #'s may be different, cables may or may not look different. New black sets exist potentially for R5 onward

below, note the 850w GRFX cables are sleeved, 1500w above aren't, see part #'s

Some vendors on eBay sell chassis + cables + cord, some sell chassis + cables (no cord), some sell just chassis + cord, some sell just chassis (no cord)

Some people may need a 15amp or 16amp C19 cord / wall plug, 3-6-8-10feet, (eBay.Amazon) Power Cord > https://www.dell.com/community/Alienware-General-Read-Only/Alienware-Area-51-Power-Cord/td-p/5548111

Typically, if you bought one or two GPUs you got one or two cable sets (set = two cables, two sets = four cables), in the days of Tri-SLI you'd get three sets (six cables). If you have four GRFX cables in there you can run dual-1080Ti / 2080 / Ti etc, if there are only two cables in there, you may need a 2nd pair. Below are all three sets

Regardless how many sets there are in someone's case, GRFX cables have part tags on them (but they're all made identical); best to find your set's part tag & order more of that part#. The Dell sales rep, once given your part#, may be able to associate other part#'s assigned to the three potential sets (black 6pin ports labeled R1 R2 | R3 R4 | R5 R6 > where each port pair gets a cable pair + unique part tag #)