In Mugwump burrow, by killing any mugwump, there is a chance to obtain this amulet:

In Catacombs, you will encounter Pylapses. He may drop Wizard boots +1:

The overseer giant may drop this hat:

Fire Wyvern Vixen may drop these bracers:


The named purple worm (Yrrrrrrch) can drop an amulet:

There is a special Wight enemy somewhere in the tower, Ga'Ro'k? it can drop these priest shoulders:

Ring of Healer can drop from the named skeleton mage, Asten:


Lich Lord can drop three different belt variants:

Belf of Constitution:

Belt of Power:


Belt of Wisdom:

From any Drow Captain, you might get Drow Captain Shield:


From Charbryn, you may get Black Mage Boots:


From any Drow Sorcerer, you may get Black Mage Robe:

There is a lost soul in the forgotten temple part of the UC that may drop these bracers(if the information is still accurate):


From the named fire/ice slimes, something like Firestom/Blizzard spawn, greater elemental rings:

From King Rhun and his wingmen, Chordir and Relurgh, you may get these items
TODO get items, upload and add links

Rhun:
Chordir:
Relurgh:

From the lava golems, you might get some fire-added 2h weapons:
TODO get items and add link

In the Evil Pet room, there are 3 evil pets. All of these have a drop.
Top left, small power bracers:


Middle, Sandals +4 of The Chosen:


Bottom left, Killrin Helmet of The Warrior:


Named Beholder and the Demilich may drop some special items, will update if get

Killrin Armor of The Mages can be obtained from Fallen Knight:


Ring of Healer can be obtained from Haler:


Panoply mail can be obtained from Lord Lon'Li'Uni'Sm:


Bard's Ring can be obtained from Damned Queen:


Spectral Bracers may be obtained from Wraith the Brute:


Chaos bracers and ring of yordan may be found here, will update when get

Got intel on Black Mage hat dropped from Lapsus the Demilich
TODO get item, put link

Killrin belt of the Warrior can be obtained from the named Goat Demon, Colony something
TODO get the correct name of the enemy


Demonic Shield can be dropped from Green Demon of Worms:


Azgan, the Armoured Demon may drop Sanctuary Shield:


Demon Lords may drop demon lord pendant:


Raas may drop killrin helmet of warrior:


additionaly, i found a ring of healer from them:


The Lom Lobon Master may drop killrin priest armor:
TODO get item, upload and add link

Not as much as special drops, but still fun, ghastly warrirors can drop their Royal Equipment.
Got five variations so far: belt, bracers, armor, shield, pants.
TODO add maybe?

On the lower level on MV, Dark Magician may drop (and it took 600 kills for me) agility belt:


In Mysterious Vault, in the level with the large garden-like room, there is a zombie named 'Unholy Zombie'. This Zombie can drop Killrin Helmet of The Priest:


Right before the pit to the Denagog, there is an enemy called Morgana. She has a chance to drop Killrin Shield of The Priest:


Right after jumping into the Pit, there are Dread Overseers. These can grop Killrin Boots of The Priest:


Arbarncin, the armoured demon, may drop agility legs:


The Denagog is a nasty acid spitting dragon, that also has a chance to drop Killrin Shoulders of The Warrior:

Got intel that Xeractor drops Crystal Mail of the Last Eyes +2
TODO get item

Through clearing Fade temple, 3 items can be obtained, one on the superior floor, and two in the basement. You might want to keep your eyes peeled for secret walls. These are all one-time drops:

Fade Cape:


Fade Bracers:


Fade Crown

From the Pagoda, agility equipment can be obtained:

Helmet:

Armor:   

Shield:   

Cape:   

Boots:   


Additionaly, Black Dragon may drop King's cloak of the dragon:

After getting to the icy cave, the Ice Golem Master may drop Crystal ice gloves of the Golem:


Through exploring the map, you will encounter this amulet in a chest:

There also are random special drops you may encounter. I will just list the images, generally places with higher level enemies have had better chances to drop these items for me:

















A reminder that not all drops are desirable: