But Butzen and Natelson are the only ones I know of.
(On that site, that is.
We know Okay, I was going to just throw a few others out, but at this point, might as well list them all. And I'm not closing that parenthesis, either! Bear in mind I'm only sharing their PPC screen name if they published under it, or if they came to plug it here and revealed their real life name as a result. So:
Kippur plugged The Tropes of Fantasy Fiction here on the Board years back.
Under her screenname, Makari published—holy cow, I didn't know the whole trilogy was out already! Need to get the other two . . . (Don't know who the co-writer is, honestly.)
Kitty Eden contributed multiple short Doctor Who fics to the anthology 101 Claras to See, which was a limited-run charity event and may not be available any more . . .
Lee Comyn is one of ours, and contributed the short story "Matching Vectors" to the M/M sports anthology Make a Play.
Jake Nelson is also a Boarder, and contributed writing for part of the quickstart guide for the tabletop RPG Relics: a Game of Angels, as well as the entirety of the Las Vegas expansion. Both are available here.
Just a month or two ago, FourMoonsWathcing published her own RPG, Swan Song.
Aaand not actually a Boarder, but the author of one of the older OFUs published The Serpent and the Peacock.
So yeah! The PPC is making a mark on the published world, no denying it! Even if the vast majority of these were published after the Boarder left . . .
—doctorlit stayed up to late assembling these links