Such cloaks are in high demand both by assassins and by those who fear them.

Duskmourn: House of Horror Commander

Whispersilk Cloak

Equipped creature can't be blocked and has shroud. (It can't be the target of spells or abilities.)
Equip {2}

Secret Lair Drop

"It bends the light somehow, rendering it—and its wearer—functionally invisible. I never would have found it if I hadn't tripped over it!"
—Quintorius Kand, research notes

The Lost Caverns of Ixalan Commander

Equipped creature can't be blocked and has shroud.
Equip {2}

"Are these magic cloaks?" asked Pippin.
"I do not know what you mean by that," answered the leader of the Elves.

Tales of Middle-earth Commander

The List

Planechase Anthology

Commander 2016

Planechase 2012

Equipped creature is unblockable and has shroud.
Equip {2}

Magic 2011

Equipped creature is unblockable.
Equipped creature has shroud. (It can't be the target of spells or abilities.)
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Duel Decks: Phyrexia vs. the Coalition

Magic 2010

Tenth Edition

Darksteel

Equipped creature is unblockable and can't be the target of spells or abilities.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery. This card comes into play unattached and stays in play if the creature leaves play.)