Frogs survived the Black Rain?
Almost everything did. Primates and Bovines were hit unusually hard. The only large populations that were completely wiped out by Black Rain are Humans, Gnu, a few dozen insect species, and most grasses. Your domesticated food sub-species went extinct too, but only because you weren't around. Dogs and Cats went feral, and today look like their wild cousins from your era. The insect and grass species that survived have thrived and diversified all by themselves.
Oh, and the Black Rain lichen evolved into something pretty benign a few centuries ago.