Unique items

A unique has a fixed base, a name and fixed lines of modifiers with value ranges. Each roll lands inside its range. Uniques always drop identified, and their flavour text is shown in italics.

84 uniques are in the game today, in five groups:

Leveling, a set of small finds for the first hours, such as Dallheim's Patched Tunic.
Early (levels 1 to 30), such as Rat King's Fang ("Gnawed off the crown it was never meant to wear"), dropped by Ketterrak, Warlord Ruzad's Cleaver or Elvenbane's Heartwood Aegis.
Mid (levels 32 to 68), such as Mooh'Tah's Bonecharm, Azerus's Brand and Zulazza's Corrupting Band.
Endgame (maps), such as Whisperblade of Yalahar, Hexmaster's Quill and The Archmage's Last Lesson.
Chase uniques, from faction Hold Wardens, the four pinnacles and Voruun Hale: Drume's Bleeding Crown, Timira's Many Voices, Oberon's Last Argument, Scarlett's Hunger and Voruun's Mortal Shell.

Where they come from

Random drops from monsters and bosses at the right level.
Each campaign boss drops its own unique the first time you kill it.
Chase uniques have a rising chance each time you kill their boss without one, and are guaranteed within a few kills: 19 Hold kills, 8 pinnacle kills or 5 Voruun Hale kills at most.

Build-enabling. About ten uniques change how a build works: some grant a keystone (Keystones), a fifth glyph slot (Glyphs), or an evasion or mana rule (Evasion, Mana before life). Only one keystone-granting item can be worn at a time. Others are deliberately "bad but fun".

Rules

A unique cannot become a runeword. Plain runes may go into its own sockets (Runes).
Corruption and Divine Orbs work on uniques (Corruption and the Vaal Orb).
Shops buy most uniques for 10 times the base's level in gold, but never the chase uniques (Vendors).
After a season, your uniques keep their stats in Standard (The Standard realm).