On my test tiles, I replicate whatever textures I might use on my work. I first roll a slab and add texture to it while it is wet, then store the unwrapped slab between two pieces of drywall until it is leather hard. This dries the slab evenly and reduces warping.
Once leather hard, I use a nylon biscuit cutter to cut as many tiles as possible out of the slab. I use a Kemper HC1 hole punch to cut a hole out of each tile. Then, I round over the edges on each test tile with a sponge, so they’re not sharp to the touch.
After the tiles are bisque fired, I can test batches of glaze and organize the tiles accordingly. I use binder clip rings (found at office supply stores) to organize the tiles. I think of these tests as swatches of color and texture, as they can easily be held up to the surface of a work in progress.
I organize swatches from the hardware store paint department on binder clip rings, too, which allows me to figure out what color combinations I’d like to explore in my glazes.