They'd be bigger than normal itzu and as black as solar cells. Fishers don't pay matter taxes, they are a city unto themselves. But fishers must protect themselves from being gathered by other fishers. Movers are a fifth profession. They move things from here to there.
Plants are a sixth profession.
They gather light and convert it to chemical energy, to be used by other itzu. Travellers are a seventh profession. They shoot out into the universe in all directions at about the speed of light, hoping to find a solar system that doesn't have any itzu yet so they can build a world to their liking. They'll be more likely to display a scene than describe one. All potentially interesting experiences will be recorded, readily available, and indexed.