Tomorrow will be the finale with , , (now level 108).
XFW, Cmags, and Loki
Good color coverage, and a cascade machine. I usually fill up Magneto's red and Loki's purple first. Fire off Mags' red to get a screen full of color and hopefully trigger a cascade, then hit Loki's purple right away and get more cascading. I let that combo fill up Mags' blue and Wolvie's Green/Black (which generate more cascades). This strategy is awesome against PVE goons and I often get through matches completely unscathed. If I am unlucky and the board is slow, Magneto's yellow shield tiles provide a nice defense while I build some AP back up.
Magneto's red is great for Wolverine's black, which gets rid of all the team-up tiles and usually allowing for enough color on the board to take out an enemy with a single hit, regardless of their health.