Gamble

Search your library for a card, put that card into your hand, discard a card at random, then shuffle.

Enlightened Tutor

Search your library for an artifact or enchantment card, reveal it, then shuffle and put that card on top.

Test of Endurance

At the beginning of your upkeep, if you have 50 or more life, you win the game.

Maze of Ith

{T}: Untap target attacking creature. Prevent all combat damage that would be dealt to and dealt by that creature this turn.

Entomb

Search your library for a card, put that card into your graveyard, then shuffle.

Clay Champion

Clay Champion enters with three +1/+1 counters on it for each {G}{G} spent to cast it.
When Clay Champion enters, choose up to two other target creatures you control. For each {W}{W} spent to cast Clay Champion, put a +1/+1 counter on each of them.

Urza's Incubator

As Urza's Incubator enters, choose a creature type.
Creature spells of the chosen type cost {2} less to cast.