the best way to decide which ones to keep is to go to the shop where you source your fish and/or look online and write down what you can get your hands on and research those to death. asking people here to list thousands upon thousands of catfish, most you wont be able to source anyway, just isnt going to happen but you may get a few of peeps like FSM but like Lupin said there are thousands of catfish and at least hundreds of different loach species.
a few loaches/botia:
clown loach
pakistan loach
yo yo loach
zebra loach
polka dot loach
dwarf/chain loach
emperor botia
black lined loach