This is almost as futile of an attempt at list-making than attempting to record the sheer mass of wandering homeless in the nation.
You would actually have better standing in making a list of characters or subject matters that HAVEN'T been tainted by the Rule 34; by attempting to encompass the sheer volume of what's essentially "fan-porn" is not only unrealistic, but impossible to fully account for as anyone could produce it at any time at an inconsistent rate of quality or specifications in what type of porn is accounted for in the material; are they fat? are they straight/gay? Are they fucking within their own species? Even with the most lenient specifications, the list you would eventually compose, if dedicated, would be titanic.
MsDD
Go to rule34.paheal.net and look around; I miss hundreds, maybe even thousands, of names.