The least toxic litter is tuft + paw Really Great Cat Litter, Petfive Sustainably Yours Natural Cat Litter, Pidan Tofu Cat Litter with Blood Test Particles, World's Best Original Clumping Cat Litter and CatSpot Coconut Non-Clumping Cat Litter.
The #1 recommended Cat Litter is Dr. Elsey's Ultra Cat Litter.
Tidy Cats Cat Litter is also a very good and recommended Cat Litter and also very popular.
The cat litter that vets recommend are cat litters made of wheat, corn or grass litter.
If your cat has any respiratory issues you should use low dust cat litter such as paper litter or wheat litter.
Clumping litter is usually best for most cats although some prefer the non clumping.
There's also low tracking litter as well.
A good cat litter is Sustainably Yours Multi-Cat Plus Extra Odor Control, which is a corn and cassava litter with a soft texture that most cats love.
It forms hard clumps on contact and emits no detectable scent or dust.
Other good cat liters are.
Purina Unscented Cat Litter.
Scoop Away Unscented Clay Cat Litter.
Arm & Hammer Fragrance-Free Clumping Cat Litter.
Fresh Step Clumping Cat Litter.