Main Deck
Psylocke can help get Sera out a turn early
Ravonna is great to curve into Jubilee or to combo Mistique & IronMan on turn 7
Mystique is good on IronMan, but best on Onslaught, good in a Pinch on Sera or second IronMan if Tribunal isnt coming
Magik is an allstar here, providing an extra draw and extra turn with 6+ energy
Wave can help get out Sera or any combo peices early
Jubilee is another allstar here, effectively drawing a card and saving energy
MsMarvel is still good and with some planning not hard to activate in either the onslaught location or adjacent
IronLad is great here, especially on the last turn when you know your last combo peice is sitting in your deck
IronMan is an essential part of the combo with Onslaught
Sera can feel clunky especially on turn 5 if you haven't played Magik yet but makes for some great end turns
Onslaught is essential for maximum power
Tribunal is key to winning games especially when there is a location that can't be played into
Other options
Only reason Zabu isn't main deck is that I don't own it
Electro works well with Nico wouldn't play without
Jeff is good filler and basically needed if you play electro
Nico is great because of the Draw 2
Demon is okay too, and 2 power is good for ironman etc
Warlock is how I used to play the deck along with
Wasp or YellowJacket to draw every card surprisingly reliably
InvisibleWoman is great for surprise value and protection against Enchantress & Rogue
Rogue can be good against other players that play Rogue or otherwise as tech
SuperSkrull is obviously nuts in the mirror match and I'm upset I don't own it
Crystal can nearly guarantee that you draw all your cards
You start the game with 3 cards and draw 1 each turn 12-3-6=3 cards left in your deck
with Jubilee and Magik leave 1 card left in your deck