Cories are generally much hardier than otos. Otos are pretty delicate as they are wild-caught using cyanide. Cories are much easier to breed in tanks so there is a large supply in the aquarium industry. :) No evil methods to catch them.
Cories like groups with a minimum of 4, preferably 6. I would suggest 6 panda cories for you, due to your tank size. Out of all the common cories, they are most delicate, but nowhere near the same way as otos. Travelling is the biggest stressor for them (when under stress they release a toxin, that builds up in their small travelling bags). However, when I transported mine by care they were generally fine (don't try it on a motorbike).
Pygmy cories (pygmaeus, hastatus or habrosus) are also an option. :)
If your tank has a good footprint, then you could consider the larger species, like peppered, bronze, julii, sterbai etc. :)