Firstly, the standard yellow sponge. They come round, but are too big and hold a lot of water. So I cut them. Inexpensive but especially after cutting them I need to watch out for the yellow bits in my clay while throwing. Though this does make a good cleaning sponge for wiping off glaze from the bottom of pots while galzing.
The elephant ear sponge. These I like. Can hold a lot or little water depending on how much you squeeze out. They are on the expensive side. They do last longer though. But $5 for sponge.. I don't think so...
This is some sort of elephant sponge which I used once and never used again. It is flat and doesn't absorb any water. Nothing good to say about this one other than its shape and size.
Then there is the mudtools sponge. It is cut in half and has been used quite a bit. Holds decent amount of water but I find it very textured. Pricey too.. $6 I think.
One of my favorites... from the Dollar store. I get four big rectangle sponges for a Dollar. And I make 5 sponges from each of them. So that is 20 sponges for a dollar. They don't feel great on first use, but after that they become flat (picture on the right) and hold just the right amount of water. Surprisingly they last longer too.
This is my recent find. Cosmetic sponges. They are cut to the perfect size and shape that I need. Hold perfect amount of water. I think I paid $3 for 20 sponges in a bag. They are great for cleaning up glazes in tight corners too like lid galleries. Let's see how long this affair lasts.