Well if you don't plan on having a clean up crew and plan on vacuuming the substrate during water changes, you would probably want either crushed coral or larger sized aragonite sand.
You can try hermits and snails but you may gradually lose them over time. Some people recommend the large strawberry hermit crabs like the ones they sell on this website. They can handle themselves with aggressive fish.
Try none I already tried like one of everything but my humu thinks they are expensive snacks just use the money on a uv and ro water and maybe a refuge that helped my tank out alot.
