The Boss powerset and leave it at that. We can salvage the PSP icons for someone else's use
Pyro should have his legendary firebirds. This will take lots of searching and scanning, but I think I've had a high-res image on file.
Sabretooth would do well with bared fangs.
Bishop MAY look nice with the M-Men banner from Bishop: Last X-Man. Or maybe that horrifying piece of history is too obscure a source?
Sunfire should have a mushroom cloud, because he is the embodiment of nuclear
fire, unlike Pyro and like Firestar.
Gambit needs some scattered cards, among which an Ace of Spades and the Queen of Hearts should definitely be present
Though every other piece of his cover art has cards in one way or another XD
Toad... leaves me worrying.
Scarlet Witch can have a congregation of mystical symbols?
Magneto needs the helmet's slightly simplified outline surrounded by mangled metal
Colossus, Wolverine, Iceman, Storm, Deadpool and Iron Man are already covered, right?
Xavier would work well with either any of his "to me, my X-Men" poses (tips of fingers to his temples, we just show the hands and the bald top of his head, surround it with FX or summat). Or just the Cerebro designs. Or any of the X-doors
I agree on Jean having the Phoenix Raptor, though we maybe should go with the stylized image off the Phoenix Uniform rather than the actual FLAME bird?
Beast... That's a great question. A transition from a jagged tear done obviously by claws to a row of test tubes and beakers? (like Echo, for instance, transitions from her face to a sword)
Rogue... Maybe a hand in her classic uniform, ungloved, touching someone's skin?
Angel! Or we do not yet plan a playable Angel? In any case, this should be feathers, either live or steel, depending on our focus on Archangel the Horseman.
Juggernaut. The Crimson Gem, transition to the helmet's outline?
Psylocke. In the older days, I would've gone for the Crimson Dawn insignia, but now... A purple slash of her blade? It has a very specific recognizable shape, after all.
Jubilee. Sparkles! Yeah, lame, but so is her powerset. Someone out there hasn't been reading Generation X.
Emma Frost. A vision of her diamond-form face with frosting on the edges of the image?
This, IIRC, covers all the XML1 and 2 playables that aren't in MUA. Right?