Ron H wrote:
The 3M conductive adhesives like the 9703 work well. Not sure how they do it
but it conducts in the Z axis ( thru the adhesive ) but not accross the
surface direction ( X & Y axis ). It's a pressure sensitive transfer
adhesive ( tape that you stick on then peel off the paper carrier leaving
the adhesive behind)
I have a roll of that. Very pricey. It contains lots of short bits
of very fine copper wire precisely aligned through the thickness of
the adhesive gel. The wires do not contact each other, so there is no
conductive path along the gel.

X-Y axis Insulation Resistance = 3.4 x 10 to the 14th Ohms/square
Z axis Contact Resistance = 1.25 milliOhm-in2

Pretty neat stuff!

Definitely. Sort of the dual of enameled wire. Conducts only at
right angles to the length.