Adafruit Product Code: 1894
Finally, the conductive material you've known you wanted but never knew you could have, its a sheet of flex PCB material! This is the stuff used to make flexible circuits, but raw and unetched. You can treat it just like 1 oz copper clad, etch it with ferric chloride (or other PCB etching systems) or cut with scissors. It may even be possible to laser or CNC engrave (we haven't tried it ourselves but we'd love to hear about it if you get any results.)
Pyralux is the brand name of Dupont's flex PCB material that's used in cell phones and other small circuits. One side of it's 1 oz copper while the other side is polyamide for strength and flexibility. The material can be manipulated through and around small areas and won't crack as easily as copper tape. Pyralux is used in a ton of consumer-grade electronics and one of the reasons why things like your cell phones have advanced from bulky and cumbersome to miniature super computers.
Comes with a 6"x6" (152mm x 152mm) square of Pyralux. It's ED-Y type copper at 35um (1 oz/ft2) and has a polymide of 25um (1 mil). The thick copper layer means it can carry a lot of current, and its trivial to solder to it. We have a little demo of it with a 1W LED above.
All of this makes Pyralux yet another great material for your next wearables project or whatever project you come up with!