Get More Characters:
Defeating Cell with specific characters gets you hidden characters, which will show up in your booster pack after the battle:
Get Guldo – Defeat Cell with Nail.
Get King Cold – Defeat? Cell with Frieza.
Get Krillin – Defeat Cell with Guldo.
Get Nail – Defeat Cell with Goku.
Get Piccolo (both Heroes and Villain sides) – Defeat Cell with Garlic Jr.
Get Trunks – Defeat Cell with Gohan.
Get Vegeta (both Heroes and Villain sides) – Defeat Cell with King Cold.