You could try breed clown loach, for the ultimate challenge!
Some monsters in there with the correct aquascaping might be tempted.
Or breed royal plecs! If you can simulate holes in river banks.
Maybe leopoldi rays or arowana maybe tigrinus or lince cats
All these would probably be firsts in the hobby and very difficult so PB would be an easier alternative.
GL with it keep us posted and do you have tank shots?
Well you could make some money if you try and breed coolie loaches =]]get like 400 of them! That'd be awsome...Maybe try and breed spiny eels..ULTIMATE CHALLENGE!
If i were able to muster enough knowledge to even attempt that, i think i would first try to see what a lot of folks were looking for in the hobby, try to successfully get that to breed and then supply that at no charge other than shipping to anyone who wanted one. (Within the law of course)