There are 16 Daedric Artifacts possible in Skyrim.

Azura’s Star or The Black Star

This reusable soul gem is rewarded for completing “The Black Star” quest.

Dawnbreaker

This One-Handed sword is rewarded for completing “The Break of Dawn” quest.

Ebony Blade

This Two-Handed sword is rewarded for completing “The Whispering Door” quest.

Ebony Mail

This piece of unique armor is rewarded for completing “Boethiah’s Calling” quest.

Mace of Molag Bal

This unique one-handed weapon is rewarded for completing “The House of Horrors” quest.

Masque of Clavicus Vile

This unique Heavy Armor helm is rewarded for completing “A Daedra’s Best Friend” quest, but only if the Dragonborn chooses to give Vile his axe instead of using it to kill Barbas.

Mehrunes’ Razor

This unique dagger is rewarded for completing the “Pieces of the Past” quest, but only if the Dragonborn kills Silus when Dagon tells him to.

Oghma Infinium

The Oghma Infinium is a powerful tome of knowledge that is rewarded for completing the “Discerning the Transmundane”.

Ring of Namira

This ring is rewarded for completing “The Taste of Death” quest.

Sanguine Rose

This unique staff is rewarded for completing “A Night to Remember” quest.

Savior’s Hide and/or Ring of Hircine

Either of these items is a potential reward for completing “Ill Met by Moonlight” quest”, in a certain manner.

Skeleton Key

The Skeleton Key is the only Daedric Artifact known not to count for the achievement, Oblivion Walker. It is obtained during the Thieves Guild quest “Blindsighted.”

Skull of Corruption

This unique staff is rewarded for completing “Waking Nightmare” quest, but only if you kill Erandur in the quest.

Spellbreaker

This unique shield is rewarded for completing “The Only Cure” quest.

Volendrung

This unique warhammer is rewarded for completing “The Cursed Tribe” quest in Largashbur.

Wabbajack

This unique staff is rewarded for completing “The Mind of Madness”.

TAKE NOTE:, some of them are missable, so be careful.