What are the legendary items in World of Warcraft

Legendary items are extremely powerful, named items which were wielded by characters of lore before. Examples of these are:

• Ashbringer (a sword forged as the ultimate holy weapon),
• Atiesh Greatstaff of the Guardian wielded by Medivh,
• The Warglaives of Azzinoth, wrested from the hands of Illidan,
• Val'anyr, Hammer of Ancient Kings,
• Sulfuras, Hand of Ragnaros,
• Peep's Whistle, summoning Kael'thas' phoenix mount,
• Shadowmourne, the most dangerous axe in Northrend,
• Thori'dal, the Star's Fury, a legendary bow.

See the related link for a full list of all items classified as Legendary in World of Warcraft. Note that some of these are only usable as part of a quest or encounter, and that your character cannot keep it.