Glint Hawk

Flying
When Glint Hawk enters, sacrifice it unless you return an artifact you control to its owner's hand.

Headsplitter

When Headsplitter enters, create a 1/1 black Assassin creature token with menace, then attach Headsplitter to it.
Equipped creature gets +1/+0.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Kor Skyfisher

Flying
When Kor Skyfisher enters, return a permanent you control to its owner's hand.

Lembas

When Lembas enters, scry 1, then draw a card.
{2}, {T}, Sacrifice Lembas: You gain 3 life.
When Lembas is put into a graveyard from the battlefield, its owner shuffles it into their library.

Experimental Synthesizer

When Experimental Synthesizer enters or leaves the battlefield, exile the top card of your library. Until end of turn, you may play that card.
{2}{R}, Sacrifice Experimental Synthesizer: Create a 2/2 white Samurai creature token with vigilance. Activate only as a sorcery.

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.)