Hank Pym, a crafter in the Marvel Heroes Game

NOTE: Credit to this goes to user "mprine " from the forums

The recipe to install a costume core is learned when your crafter reaches L10. Installing a core will make the costume require your hero to be L27 to equip it. The cost is 85k, in addition to the core and costume it also requires various refined particles (crafting materials) which drop commonly throughout the game.

Cores will add extra attribute points or other bonuses like special item find to your hero.

Hero Core
Black Panther Vibranium
Black Widow Vibranium
Captain America Vibranium
Cable X-Gene
Colossus X-Gene
Cyclops X-Gene
Deadpool Adamantium
Dr. Strange Promethium
Emma Frost X-Gene
Gambit X-Gene
Hawkeye Vibranium
Hulk Radioactive Isotope
Human Torch Radioactive Isotope
Invisible Women Radioactive Isotope
Ironman Adamantium
Jean Grey M'Kraan
Loki Promethium
Moon Knight Adamantium Alloy
Ms Marvel M'Kraan
Nightcrawler X-Gene
Punisher Adamantium
Rocket Raccoon M'Kraan
Scarlet Witch Promethium
Spiderman Radioactive Isotope
Squirrel Girl X-Gene
Taskmaster Vibranium
Thor Promethium
Wolverine Adamantium