My cats use your regular, run-of-the-mill litter pans. They are the kind that has the lip that comes apart so that you can lock in a litter pan liner (though I don't use liners in my litter boxes). I like having the rim because it helps contain the litter when the kitties scratch. They're not big-time scratchers, but any litter containment is good in my book.
I also have a couple of small, plain litter boxes for the kitties' crate and carriers (in case of an emergency or travel). They are tiny, but would work in a pinch if necessary.
As far as how many litter pans I have, well, lets see. I have two in my bedroom presently as well as two in the laundry room downstairs, one in the guest bathroom downstairs, and one in the spare bedroom upstairs. Oh, and I also have one in the family room in the basement (it's in the walk-in down there). The basement is not fully finished and the second portion is closed off and just for storage so I only need one down there. I may have a bunch of boxes, but it makes cleaning a lot easier and it means there is always a box available to one of the cats. I'd rather have to scoop more or have litter pans around the house than have cats not using their boxes. And, it works for us.
I also have a couple of small, plain litter boxes for the kitties' crate and carriers (in case of an emergency or travel). They are tiny, but would work in a pinch if necessary.
As far as how many litter pans I have, well, lets see. I have two in my bedroom presently as well as two in the laundry room downstairs, one in the guest bathroom downstairs, and one in the spare bedroom upstairs. Oh, and I also have one in the family room in the basement (it's in the walk-in down there). The basement is not fully finished and the second portion is closed off and just for storage so I only need one down there. I may have a bunch of boxes, but it makes cleaning a lot easier and it means there is always a box available to one of the cats. I'd rather have to scoop more or have litter pans around the house than have cats not using their boxes. And, it works for us.