The biggest thing is going to be if the frags you grow are pest/illness free. When I was asking someone about their live rock and if there were any of x specific pests, they disappeared so I can only assume the rock contained at least one of the pests I listed. We have had a gamete of pests/illnesses from corals we purchased.
If you had a large selection of palythoas and zooanthids, I imagine you would get some interest.
On our next tank, I am planning on only buying from aquaculture facilities known to not have pests (ORA and cultivated reef).
Really palys and zoas are coming back big time, not so much the easy pieces to get like rastas, eagle eyes, ect.,but the rarer ones, any kind of rainbows, ect. High end shrooms are liked too, but not as much. If you have the room everyone loves euphyllia but they don't grow that fast and take up a lot of room.