The best bedding for pet rabbits is generally considered to be paper-based bedding, such as shredded paper, paper pellets, or recycled paper bedding. This type of bedding is safe, absorbent, and less likely to cause respiratory issues compared to some other types of bedding like cedar or pine shavings. It is important to avoid using bedding made of clay or clumping materials, as these can be harmful if ingested by the rabbit.