Mishra's Foundry

{T}: Add {C}.
{2}: Mishra's Foundry becomes a 2/2 Assembly-Worker artifact creature until end of turn. It's still a land.
{1}, {T}: Target attacking Assembly-Worker gets +2/+2 until end of turn.

Play with Fire

Play with Fire deals 2 damage to any target. If a player is dealt damage this way, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Hexgold Halberd

For Mirrodin! (When this Equipment enters, create a 2/2 red Rebel creature token, then attach this to it.)
During your turn, equipped creature has first strike and trample.
Equip {2}{R}

Feldon, Ronom Excavator

Haste
Feldon, Ronom Excavator can't block.
Whenever Feldon is dealt damage, exile that many cards from the top of your library. Choose one of them. Until the end of your next turn, you may play that card.

Mountain

Lightning Strike

Lightning Strike deals 3 damage to any target.

Monstrous Rage

Target creature gets +2/+0 until end of turn. Create a Monster Role token attached to it. (If you control another Role on it, put that one into the graveyard. Enchanted creature gets +1/+1 and has trample.)

Etching of Kumano

Haste
If a creature dealt damage this turn by a source you controlled would die, exile it instead.

Kumano Faces Kakkazan

(As this Saga enters and after your draw step, add a lore counter.)
I — Kumano Faces Kakkazan deals 1 damage to each opponent and each planeswalker they control.
II — When you next cast a creature spell this turn, that creature enters with an additional +1/+1 counter on it.
III — Exile this Saga, then return it to the battlefield transformed under your control.

Kumano Faces Kakkazan // Etching of Kumano

Electrostatic Infantry

Trample
Whenever you cast an instant or sorcery spell, put a +1/+1 counter on Electrostatic Infantry.

Phoenix Chick

Flying, haste
Phoenix Chick can't block.
Whenever you attack with three or more creatures, you may pay {R}{R}. If you do, return Phoenix Chick from your graveyard to the battlefield tapped and attacking with a +1/+1 counter on it.

Monastery Swiftspear

Haste
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Sokenzan, Crucible of Defiance

{T}: Add {R}.
Channel — {3}{R}, Discard Sokenzan, Crucible of Defiance: Create two 1/1 colorless Spirit creature tokens. They gain haste until end of turn. This ability costs {1} less to activate for each legendary creature you control.

Bloodthirsty Adversary

Haste
When Bloodthirsty Adversary enters, you may pay {2}{R} any number of times. When you pay this cost one or more times, put that many +1/+1 counters on Bloodthirsty Adversary, then exile up to that many target instant and/or sorcery cards with mana value 3 or less from your graveyard and copy them. You may cast any number of the copies without paying their mana costs.

Squee, Dubious Monarch

Haste
Whenever Squee, Dubious Monarch attacks, create a 1/1 red Goblin creature token that's tapped and attacking.
You may cast Squee, Dubious Monarch from your graveyard by paying {3}{R} and exiling four other cards from your graveyard rather than paying its mana cost.

Barbed Batterfist

For Mirrodin! (When this Equipment enters, create a 2/2 red Rebel creature token, then attach this to it.)
Equipped creature gets +1/-1.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Goddric, Cloaked Reveler

Haste
Celebration — As long as two or more nonland permanents entered the battlefield under your control this turn, Goddric, Cloaked Reveler is a Dragon with base power and toughness 4/4, flying, and "{R}: Dragons you control get +1/+0 until end of turn." (It loses all other creature types.)