A lot of people have had something to contribute to this partial powers system, and I'd like to credit them here, if I may. I guess the main body of it is currently taken care of and maintained by me (Doyce Testerman).
The original concept was thought up by Gideon Weinstein, and you'll sometimes see this referred to as the 'Weinstein Partial Powers System'. Scott Turnbull made some modifications before I ended up tending it, but didn't document exactly what was his and what was Gideon's.
The Jewel of Judgment section and the Broken Pattern section were my first additions to the mix, and Rey Herrera and I worked out the Advanced Trump stuff.
Randy Trimmer and I worked out the way to Combine all of Sorcery, Conjury, and Power Words under the grand heading of Magick.
Inspiration from Rey H. and Juli Halbur-Herrera brought me to the Twilight powers.
The Fey (Fae) Powers and Dream Magick additions to Magick were originally designed by Vramin the Green.
The Crossroads power is all mine, and doesn't have anything to do with the Zelazny novel of the same name. :)
The Matrix power was originally designed as the Representation and Vortex by Daniel Jacobsson and his GM, Tim Wilbanks. After playing in Tim's PBMush for a bit, I reworked that power for my own use including the Basic applications and a few advanced, and then turned the Matrix over to Scott Nolan, who refined it and added the final advanced applications.
Cathy Klessig and Daric Kozlowski designed a great representation of the 'mirror world' powers (as seen in one of Zelazny's last Amber short stories, The Shroudling and the Guisel), which Daric then brought to me for the Brokedown Palace campaign.
The Allies text (I think) originally came from the LintKing.
I completely reworked the Items section, inspired by the work of ArrefMak, which can be found here.
Parts of Exalted Trump were originally conceived by Pattern Ghost, reworked by Rey Herrera, and finally by me.
Finally, the indomitable Randy Trimmer designed the powers of 'The Shell that is Broken at the Center of the World' and 'The Blood of the Beast on the Pole' -- both referenced obliquely in one of the Amber Books, as well as the Master of the Void power, which makes for a great Abyss-related ability.
As you can see, this effort has been one of great longevity and great affection, and I hope it brings you some small amount of amusement or use.