Immense numbers. Quarries destroy them by the (enormous) truckload all the time, unexamined, god knows what cool unknown stuff has been ground up. Entire kinds of rock are basically made of fossils, not even always the really tiny kind (note: fossils can be microscopic!)

Then consider what's buried under the sea, totally inaccessible. Or under the ice at the poles.

It's a lot of fossils. And that's without even getting into questions like "what counts as a fossil for these purposes?", just any halfway sensible answer is going to leave you with an unfathomably big number, no need to even dig (ha, ha) into the specifics.

The places scientists go to dig up fossils are mostly where a particular stratum happens to exist (the crust gets recycled, so much of the oldest stuff is simply gone in most of the world) and happens to be exposed near the surface. Those same kinds of (for the more common strata, anyway) exist all over the place, just buried too deep to get at except, sometimes, during commercial excavation for things like mining (and then most of it's just gonna be destroyed without a look).