Jack-in-the-Mox

{T}: Roll a six-sided die. This ability has the indicated effect.
1 — Sacrifice Jack-in-the-Mox and you lose 5 life.
2 — Add {W}.
3 — Add {U}.
4 — Add {B}.
5 — Add {R}.
6 — Add {G}.

Inhumaniac

At the beginning of your upkeep, roll a six-sided die. On a 3 or 4, put a +1/+1 counter on Inhumaniac. On a 5 or higher, put two +1/+1 counters on it. On a 1, remove all +1/+1 counters from Inhumaniac.

Hoisted Hireling

Hoisted Hireling has flying as long as it's being held above the battlefield.

Swamp

Enter the Dungeon

Players play a Magic subgame under the table, starting at 5 life and using their libraries as their decks. The winner searches their library for two cards, puts those cards into their hand, then shuffles.

Poultrygeist

Flying
Whenever a creature dies, you may roll a six-sided die. If you roll a 1, sacrifice Poultrygeist. Otherwise, put a +1/+1 counter on Poultrygeist.

Bat-

Flying
At the beginning of each end step, if an opponent lost 3 or more life this turn,
Augment {1}{B} ({1}{B}, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

Skull Saucer

Flying
When Skull Saucer enters, destroy target creature and put your head on the table. Sacrifice Skull Saucer when your head stops touching the table.

Snickering Squirrel

You may tap Snickering Squirrel to increase the result of a die any player rolled by 1.

Infernal Spawn of Evil

Flying, first strike
{1}{B}, Reveal Infernal Spawn of Evil from your hand, Say "It's coming!": Infernal Spawn of Evil deals 1 damage to target opponent or planeswalker. Activate only during your upkeep and only once each turn.

Dirty Rat

When this creature enters, target opponent discards a card.

Infernius Spawnington III, Esq.

Flying, first strike, trample, haste
This spell costs {3} less to cast for each card you've revealed this turn.
When Infernius Spawnington III, Esq. enters, you may say "I'm here." If you do, it deals 3 damage to target player.

Destroy target creature with reminder text. (Reminder text is any italicized text in parentheses that explains rules you already know.)

Jumbo Imp

Flying
As Jumbo Imp enters, roll a six-sided die. Jumbo Imp enters with a number of +1/+1 counters on it equal to the result.
At the beginning of your upkeep, roll a six-sided die and put a number of +1/+1 counters on Jumbo Imp equal to the result.
At the beginning of your end step, roll a six-sided die and remove a number of +1/+1 counters from Jumbo Imp equal to the result.

Booster Tutor

Open a sealed Magic booster pack, reveal the cards, and put one of them into your hand. (Remove that card from your deck before beginning a new game.)

Underdome

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to pay Un-costs.

Infernal Spawn of Infernal Spawn of Evil

Flying, first strike, trample
Once each turn, while you're searching your library, you may pay {1}{B}, reveal Infernal Spawn of Infernal Spawn of Evil from your library and say "I'm coming, too!" If you do, Infernal Spawn of Infernal Spawn of Evil deals 2 damage to a player of your choice.

Stinging Scorpion

When this creature enters, target creature an opponent controls gets -1/-1 until end of turn.

Acornelia, Fashionable Filcher

Whenever you cast a spell with a squirrel in its art, you get {A} (an acorn counter).
Whenever a Squirrel you control enters or dies, you get {A}.
{2}{B}, Pay X {A}: Target creature gets -X/-X until end of turn.
{G}, Pay X {A}: Target creature gets +X/+X until end of turn.