A blenny, like a lawnmower blenny. They are bottom dwelling, they scrounge around for food on the bottom almost constantly, they're omnivores, they're curious and mostly peaceful. These are some of the comparisons I've been able to make.

That's an interesting idea. I've never come across a SW fish like a cory, but it's like not ever coming across an animal that's like a cat, isn't it? Sure, you can attribute certain characteristics to cats and find them in other animals; such as, a rabbit could be described as "like a cat" because they're both fairly independent acting and alert and curious. But they're also both very individual animals and those traits could be used to described many animals. Even some breeds of dogs, like spits breeds, are often more independent and aloof acting than your typical dog.

So all in all, I don't think you could ever find another fish that's equal to a cory but maybe you could find a fish that fits some of their characteristics