Any 60-card deck (including basic lands) is immediately playable and powerful enough to compete in the Pioneer format.

Dimir Control (Blue-Black)
Thwart your opponents' plans and implement your own.

Gruul Masher (Red-Green)
Accelerate your mana production early and crush your opponents with huge creatures.

Izzet Phoenix (Blue-Red)
Cast tons of spells and fly in with spell-loving creatures.

Orzhov people (White-Black)
Strengthen your army with anthems and keep your opponent off balance.