I liked the
little plastic containers that mints come in for hatchlings, just pull the lid off and cut a little door in it. Sturdy and washable.
Mine liked TP and paper towel tubes when they were small enough. Now I use the bigger tubes that commercial paper towels come on, and the ones that a rodent's timothy hay comes in.
I've also used cheap plastic bowls, using a soldering iron to make a door.
I use a small cat litter box for one, cut a door in it.
Recently I've used the black plastic tray that some frozen enchiladas came in.
I use cereal boxes for my big two-pound corn. She likes hiding in it or sitting on top of it.
I feel like I'm always on the lookout for things the snakes can crawl through and hide in