Our most productive plant is K. laetivirens, an unusual succulent that yields many plantlets around the edges of its leaves. There are varieties: ours is bright green, resilient, and likes small pots.
We grew a large one (to truly become a mother of thousands). We cultivate its many plantlets in glass pots and anonymously leave them for others in our neighbourhood in Toronto.
Just a couple batches so far, but we've recent set up an LED system to accelerate plantlet growth in the pots. We hope to leave around 100 pots this summer. Thank you for the link re: orchids, it's a great project!