CM, Finder is pretty much the god of creative, amature bards... and decay? As of the end of the Finder's Stone Trilogy, he had exactly 2 priests, and 1 temple. The only reason he's a god is because he killed Moander and absorbed his power... The power of decay and general ooziness
He doesn't like those powers, so he's trying to find his niche without stepping on the toes of Deneir, Oghma, and Tymora. He's up to a rough start...
As far as a count of gods, all I can say is that in addition to the human gods, the elves have a pantheon, the dwarves do, the orcs do, etc... Don't try counting. Even the Kobolds have a pantheon...
Ao is the ruler of all gods; most pantheons have their own rulers (under Ao, of course). Ao appointed nine (I think) gods to govern the Balance and forced them all to study the Tablets of Fate before bedtime every night. Then he told them to memorize their duties and broke the Tablets.
FR theology is confusing, just pay attention to the gods you need and you'll be better off...