Okay - first of so called "freshwater sharks" for home aquaria - aren't real sharks, they're basically a type of carp or catfish (depending on the species).
As for true sharks that stay under 2 ft. There aren't many that are generally available for home aquaria.
But here's a list of those that are available. Virtually all are called Catsharks.
Izu Catshark - max 16"
Cloudy Catshark - max 20"
Chain Catshark - max 20-24" (depending on sub-species)
Australian Marbled Catshark - max 24"
Bali or Banded Coral Catshark - max 18-20" (very very rare).
By the way Ken, I can confirm that the coral cat on the live aquaria site a month ago was a Bali coral cat. It didn't end up in the states, but is in good hands and the search is on for a mate. Thanks for pointing out that it looked off.
burma bamboo/chiloscyllium bumensis, indian bamboo/chiloscyllium indicum,freycinets epaulette shark/hemiscyllium freycineti. all are benthic sharks but real sharks none the less, the bamboo, ime tend to eat alot more than your epualettes and grow larger faster depending on species. i find the bamboos more pushy and a little bit more agressive than say a speckled epualette . it tends to be a bit more of a recluse prefering to come out at night i find most epualettes to be a little shy