Vermin in the sewers would be another good one for bats a mix of killer croc and man bat but, less jobbing..
Carrion would be good for bats but i can see him killing bats if he ever touches him...
Demo goblin another warped reflection of bats but demonic and supernatural...
these guys would fit perfectly in Gotham with bats trying to figure out murder cases and what their deal is..
Hobgoblin also a good one hunting bats down b/c he is paid to..