Might check with a plant nursery- some people use driftwood in houseplant arrangements. Or you could always go hiking...I found the best curvy driftwood branch while kayaking the nearest river- about 6.5' long, it sure was awkward dragging it home, lol, but I'm glad I did.

Might get lucky in a thrift store too, you never know.

I'm a BIG fan of wedging a few branches crossways diagonally for my snakes to climb on...fortunately for me they grow on trees around my place. (The branches...not the snakes! )
When I trim things out of my yard, I keep the best branches back for replacements.