Those 2mm brake cables (Shimano?) from the very early 90's. Absolutely no stretch at all. Is mine the only bike with the original cable from 1991 still on it? I have lost count of the number of new block sets the bike has got through but the cable lives on!!
Ah - that reminds me - Clark's Powerglide cables with the slippery plastic liner.
I had some on my BMX that improved the brakes hugely.
AND (just as important) the outers came in every colour imaginable.