Glowforge sells veneer with 3m backing. You can also buy veneer sample packs with lots of options online. Those would be semi-flexible. Cards of Wood sells veneer that can go through a printer. You can then apply adhesive either via a roll (3M) or with something like a Xyron.
Here’s what I did with the Cards of Wood paper-backed veneer and my laser printer (also my laser cutter!):