Certain items were only available for a certain period of time, then were either modified or removed from the drop pool. Others were only available through specific leagues or race seasons. These items are now only obtainable from players who possess existing copies.
League-specific items
League-specific items can only be obtained when the corresponding league flag is active (i.e. during the league, from Zana mods, or during events).
League-specific base items
In some challenge leagues, base items are created which do not drop in permanent leagues. One way of acquiring them is to corrupt unique items and gain corrupted rare items then use vendor recipes to gain back a unidentified rare item.
Talismans can be obtained in the permanent leagues as Safehouse rewards that linked to Thane Jorgin the Banished. Certain divination cards also granted random talismans, as well as some Delve rewards chest. They can also drop from monsters or chests in Legion encounters.
League-specific unique items
In most challenge leagues, unique items are created which do not drop in permanent leagues. These items can sometimes be found in maps by using Zana's Map Device. Also the following methods may allow league-specific unique items as random drops (except that some items may only drop from a specific league-boss):
- Beastcrafting.
- Divination cards as listed on the item's page.
- Cameria's Transportation Safehouse chests.
- Level 2-3 Altar of Sacrifice at Hall of Offerings/Apex of Ascension incursion rooms.
ChancingOrb of ChanceStack Size: 20Upgrades a normal item to a random rarityRight click this item then left click a normal item to apply it.
Shift click to unstack.
or using 
Ancient OrbAncient OrbStack Size: 20Reforges a unique item as another of the same item classRight click this item then left click a unique item to apply it.
Shift click to unstack.
in a map crafted with the corresponding map mod using Zana's Map Device. For example, HeadhunterHeadhunter
Leather BeltRequires Level 40+(25-40) to maximum Life+(40-55) to Strength
+(40-55) to Dexterity
+(50-60) to maximum Life
(20-30)% increased Damage with Hits against Rare monsters
When you Kill a Rare monster, you gain its Modifiers for 20 seconds"A man's soul rules from a cavern of bone, learns and
judges through flesh-born windows. The heart is meat.
The head is where the Man is."
- Lavianga, Advisor to Kaom in a map crafted with Zana's Nemesis mod.- Time-Lost IncubatorTime-Lost IncubatorAdds an incubated League-specific Unique item to an equippable item
Item drops after killing # monstersLeague-specific Unique ItemRight click this item then left click an item to apply it. The Incubated item drops after killing a specific number of monsters.. - A Hidden Heirlooms crate in the Azurite Mine.
- A rare monster possessed by a Tormented Graverobber.
- Cadiro Perandus can offer a league-specific unique item in exchange for Perandus CoinsPerandus CoinStack Size: 5000Trade coins to Cadiro Perandus.
Shift click to unstack.. - "Drop a Unique item" bargain option in an encounter with the Immortal Syndicate.
- Several monsters and chests of Legion encounters.
- Map bosses under high Atlas Awakening Level (+#% chance for an additional Unique Item to drop from Unique Map Boss)
- The Coward's TrialThe Coward's Trial
Cursed Crypt MapMap Level: 80
Map Tier: 13
Guild Character: ÅContains waves of Monsters
Contains additional waves of Undead Monsters
<0 to 7 random additional waves modifiers>For his sins he was hunted in his sleep,
judgement wrought of twisted nightmare.
The Coward bound his dreams to stone, awaiting
another to walk the path of true atonement.Travel to this Map by using it in a personal Map Device. Maps can only be used once. Map boss (ilvl 100)
Note: For league-mechanics that have been introduced to core, the unique may be either enabled as world drop or boss drop. For example, killing bosses of their respective league: bosses of Warbands-themed map, Abyss/Delve/Synthesis bosses, The Vaal Omnitect, Mastermind, The Pale Council; finishing Beachhead maps, Breachlords' domains and Safehouses; killing monsters in Breach; doing Prophecy and open Perandus chests, etc.
Legacy
Legacy items
Legacy items are discontinued versions of items that have been subjected to balance changes which do not affect existing copies of the item. Due to their limited availability, their prices can be high.
Most legacy items can be updated to their newest stats by using a 
Divine OrbDivine OrbStack Size: 10Randomises the numeric values of the random modifiers on an itemRight click this item then left click a magic, rare or unique item to apply it.
Shift click to unstack.
or 
Blessed OrbBlessed OrbStack Size: 20Randomises the numeric values of the implicit modifiers of an itemRight click this item then left click another item to apply it.
Shift click to unstack.
on it. Note that this will not work on unique items that had modifiers added or severely changed, like 
Kaom's HeartKaom's Heart
Glorious PlateQuality: +20%
Armour: 931Requires Level 68, 191 StrHas no Sockets
(20-40)% increased Fire Damage
+500 to maximum LifeThe warrior who
fears will fall.
. In that case, a Divine Orb will only change the present mods to the new value, and not add additional ones. These orbs won't work when the base item was changed, either.
Legacy names
Certain unique items have had their names changed. Those items that were obtained before the name change was implemented will forever retain the old name.
Legacy modifiers
Some item affixes were changed or removed from the drop pool altogether for balance reasons.
Removed items
Certain items have been removed from the drop table, usually because they were replaced with another item. These items can only be obtained by trading with other players in a permanent league.
Event Items
Event Rewards
Each race and player-versus-player season offers rewards of existing items with alternate art for reaching certain point breakpoints within the season. Event-specific rewards (and alternate art counterparts of these) are also offered for placing well in the race or the season. All rewards are placed into remove-only tabs that can be viewed from any league, but once removed, they remain in the league they were taken into and cannot be transferred to other leagues. These rewards cannot be viewed or removed from the stash in temporary leagues until four weeks have passed since the beginning of the league.
Event Prizes
At the end of each event and at the end of the season, unique trophy items are distributed among the best race and pvp participants. They follow the same rules as Event Rewards.