Feline Pine. It works great and the cats love it.

World's Best.

The stuff in the yellow plastic bucket with the orange lid.

I buy. 40# bag of equine pine from tractor supply lasts forever. $6

'World's Best': it clumps without being dusty.

I use Tidy Cat clumping. I scoop daily, bag it all and toss into the garbage. The remaining litter never seems to need dumping, I just replenish with more as needed.

I use anything available. The litter goes in the bottom of the tray, a plastic grill then fits over the top of that to allow the liquid to flow through. However that is reduced by putting paper towel down on top of the grill. Puss Puss tells me when she has soiled the paper and like a good slave I replace it either by wrapping up the poo and flushing it down the toilet or the simply wet paper is rinsed, sprayed with bubble gum disinfectant and eventually by the bagful recycled.
Apart from two times recently when she has managed to step in sloppy poo and then leave paw prints across the lino and apart from my irritation at having her meowing at me to put fresh paper down whilst in the middle of doing something, the system has worked well and kept her and I healthy. The midden of dumped clay in the corner of the garden after about 4 years is now 18" high and about 3'x4' in size. Last year i managed to grow two hollyhocks in it. One flowering. I will have to enquire if the gardeners have better cover.

Swheat Scoop. Clumping and more environmentally friendly. One bag usually lasts 3-4 weeks for one cat.

The litter does not matter. Clean out the box once a day for an odor free environment...I had 6 cats 4 litter boxes. No cat odor smell at all. I changed the litter once a week and added baking soda to the litter.

My two kitties use plain clay litter from Walmart which only costs $1.17 per bag that fills one litter box every two weeks. Each week I dump the two litter boxes in the local landfill for free. All together is costs $60.84 per year. (Not including tax)

I use the Breeze system by Tidy Cat. It works pretty well for me. There is an absorbant pad liner that goes in the tray on the bottom and odor absorbing pellets for the litter. Just scoop the poop daily and and change the pads weekly. You can get pads for it on Amazon that are cheaper than the Tidy Cat version.

I use Fresh Step low tracking litter. I also liked Dr. Elsey’s Precious Cat, but the one I preferred has become increasingly hard to find. I tried the self cleaning one ages ago and it just wasn’t strong enough for bigger clumps and poops, so it would constantly get clogged. What a waste of a couple hundred that was! Now I use a sifting box and it seems to be going well

I mostly use a pine product. It is not clumping. Haven't tried the self-cleaners. I figure it only takes one time for the cat to be there at the wrong moment, to incur life lasting psychological trauma....