Well...if we take
Babylon 5 as a comparison, there are at least nine "First Ones" races that we know of, and there
were definitely more than this at some point, but the others have "passed beyond the rim", either metaphorically or literally. An individual of any one of them could appear "godlike" to humans and other equivalent races, but they're just an ordinary individual from a species that is billions of years older than we are.
If we look at the list of "
powerful and godike beings" on
Memory Alpha, and ignore individuals that are just ordinary entities that temporarily gain superpowers, there are around thirteen depending on where you want to draw the line. And some of those, like the Cytherians or the Nacene, are just "much more advanced than the Federation" without
actually being godlike and non-corporeal, like the Q or the Douwd. So it's actually quite similar, and there aren't as many as you might think.
Given that our galaxy is over 12 billion years old and the Earth is somewhat less than 5 billion years old, there's a HUGE amount of time for any number of alien races to have arisen, evolved, and developed to become "godlike" before we crawled out of the primordial slime. I don't think there are all that many, it's just the ones who are still around are
really damn powerful and therefore easy to spot.