Okay, first things first. "Why PSP?" you will ask.
On the left, we have a DXT3-compressed iconset from XML2PC. Note the dead outlines and poor transitions.
On the right, however, we have the palletized XML2PSP version. Note the smooth transitions and lack of colour bleeding. This is because the pallettized format calls for per-pixel storage, while DXT3 stores pixels in blocks of four to achieve its compression (which kills the colours). Does that answer the question? Good.
First, the XML2PC exclusives, which are not available elsewhere. Preview:(raw BMP dumps here)
Left to right: Pyro, Gladiator(!) and Sabertooth. I don't really know who the game refers to as "Gladiator", but these icons are unique and unused. Enjoi.
Now for the pallettized prettyness. These are in PNG, per-pixel accurate with all the colours packed in. This is as good as it gets.
Apocalypse (from the Harmonic DNA fight sequence)
Unswizzling takes up time, so this WILL take a while more. I will also put up ALL XML2 icons of the characters that made it into MUA as playable (as seen here with Colossus) since their icons in XML1, 2 and MUA are entirely different, as you can probably see already. Yesss. We shall pick out the icons we WILL use, and others will be salvaged for other characters, or to be re-drawn into other characters