Shredded aspen, a fibrous wood product, is also good for medium and large snakes. Sand, soil, sawdust, and kitty litter are not good. Sand and soil don't dry well, and a wet cage encourages skin diseases. Dust from sawdust or kitty litter can give a snake incurable pneumonia. Cedar chips may be toxic.
Most snakes do very well in a simple cage.
All require a water bowl and some sort of hiding place. Hatchlings will coil up in the crevices in a loosely wadded piece of newspaper. A closed cardboard cereal box with a hole in a corner works for larger snakes. If the box is too big for the snake, fill it with loosely wadded newspaper. Tree snakes need a branch.