Wire for harsh environment
You may want to try horrible to work with fiendish to solder or otherwise terminate super nasty BUT stunningly robust &amp; flexible &quot;tinsel&quot; - as used in old telephone and instrument cords when people wanted them to last.
A surprisingly large number of people still supply it.
Good commentary - 2011 Designing Cables for Increased Flexibility They say:
Tinsel Wire

For low voltage applications, tinsel wire offers the greatest degree of flexibility.
Tinsel wire is made by flattening the conductor material into a ribbon and then spirally wrapping one or more conductors around a strong fabric core.  Tinsel conductors are typically made of copper and are often plated with tin or silver.  Because the fabric core is what gives tinsel wire its strength, the conductors can be made very thin and flexible.

Micro photo of a single strand of tinsel wire – flattened conductors wrapped spirally around a strong fabric core

Tinsel wire made up of seven strands of tinsel conductor
Due to the nature of the construction; tinsel wire is more expensive than common stranded copper wire.  However in applications where both high flex life and tensile strength is required, tinsel wire, or cable made up of tinsel conductors, may be the best design choice.


By the containerload, probably
And many more aaand some of these are even relevant - ignore the Christmas decorations.
Wikipedia not marvellous