Let's see...Grand piano, EP, 4 or 5 guitars, a couple of Strings, Fiddle, Steel guitar, 3 Saxophones, a Trumpet, a brass bed occasionally, 4 or 5 organs, a vocal sound or two, Vibes, Marima once in a while. . . that's about it. Maybe 20 or 30.
Good question!
I could get by with even fewer if I had to. But I do want them to be realistic. I strive to sound like a small combo most of the time, rather than an orchestra.
I understand that people who do different styles of music than what I do have a much different set of needs. I don't do New Wave, Rap, Hip-hop, Oriental, Middle East, and very few Latin. I'm sure there are many more types of music I don't do.
I suppose that's why the makers offer such a huge number of sounds, trying to make a "one size fits all" keyboard.
DonM