Naelwyn
Non sum qualis eram
I tend to be really, really stringent, so here's the stuff that's made the cut well enough I'm willing to recommend it.
D&D Second Edition, Planescape Setting.
http://www.ralf.org/~krlipka/ps/fiction/archive/firedust.html
Fire and Dust, James Gardner.
Eliezer Yudkowsky (Research Fellow - Machine Intelligence Research Institute. Yes I am totally serious.), Harry Potter and the Methods of Rationality.
http://hpmor.com/
Collected Works of Gabriel Blessing. (Numerous Series crossovers that I've enjoyed.)
http://www.fanfiction.net/u/1263379/gabriel-blessing
http://www.fanfiction.net/s/8096183/1/Harry-Potter-and-the-Natural-20
D&D Second Edition, Planescape Setting.
http://www.ralf.org/~krlipka/ps/fiction/archive/firedust.html
Fire and Dust, James Gardner.
Eliezer Yudkowsky (Research Fellow - Machine Intelligence Research Institute. Yes I am totally serious.), Harry Potter and the Methods of Rationality.
http://hpmor.com/
Collected Works of Gabriel Blessing. (Numerous Series crossovers that I've enjoyed.)
http://www.fanfiction.net/u/1263379/gabriel-blessing
http://www.fanfiction.net/s/8096183/1/Harry-Potter-and-the-Natural-20