I'd say most use calcium chloride because almost everyone likes the effects of chloride on beer. Many beginners use calcium sulfate (gypsum) because many beginning recipes are for ales and British ales are often brewed with gypseous water. And many people like the effects of sulfate on beer as well though it is not as universal as with chloride. Some will add some magnesium (usually as the sulfate) but that's done mostly when trying to emulate a particular water ion profile.
Bones are mostly hydroxyl apatite (calcium hydroxyl phosphate) as are teeth. Those don't dissolve in the animal's body and they won't dissolve in brewing water either. So the answer is no, no one uses bone meal.
Some of us are discovering the advantages of brewing with soft water. We will usually add enough calcium chloride to RO or DI water to get the calcium up to 20 mg/L or so (50 ppm as CaCO3).
