What style are you going for? You can use anything from a tree branch to plumbing pipes.
Wonderful! Here are some options for you!
Try using some decorative bamboo!
Here's how I made curtain rods from plumbing parts for my son's bedroom. https://www.simplicityinthesouth.com/youre-making-what-galvanized-curtain-rods-from-plumbing-parts/ I'm also using them for my laundry room but I painted everything black and used black curtain ring clips instead.
Electrical conduit, PVC pipe. Can be painter. Both are cheap.