I make my own out of Cat 5 or Cat 6 from eBay, cut any connectors off, twist different colors, add WBT type connectors from Parts Express or Amazon
Add a few feet to allow extra length needed when you twist them.
Pay attention to the details: I go for pure copper, foil wrapped, 4 shielded twisted pairs, prefer stranded to solid core,
8 x 24awg = 15 awg
If you can find it, 8 x 22 awg = 13 awg. (smaller awg # is larger)