Here are all the scripts South Park Studios was able to publish, up to episode 508, before being told to take them down.
Buurin (Keith Hui)
The G Man|
And many others who write in from time to time.
In keeping with Matt Stone's wishes, I moved the Kenny's Wisdom (Kenny Dies) link here and will say that I post my best guesses on what Kenny says, so they are not authoritative, just informational.