I'm not sure there ARE "many pros" in the world of autoharping. Professional autoharpers? Almost an oxymoron. :)

Well, I count at least 70 on the website you linked.

But compared to, say, guitarists, I suppose you're right.

OS 21's are renowned for jamming (mechanically, not musically) and Chroma 21's for broken chord bars.

I'm not a pro, I'm not even a musician (musicians have talent), I'm purely a music lover and autoharp hobbyist.

It would be hard for me to assemble a 10 song set of either/both traditional folk songs or pop favorites that would require more than 12 chords. But I have upwards of 30 chord bars, some of which I haven't used in years.