If you have a cat, you also need to have a litter box. Unfortunately, all types of litter can have problems. Clay litter can be dusty and contain odium bentonite, silica and other small particle materials that could lead to respiratory disease. Litter made from recycled paper, wood, or corn could contain pesticide residue.
Basically the best litter is the one your cat will use and one that keeps down the odor. Since this isn’t always possible, you could always try toilet training your cat and avoid litter boxes altogether.