Some of these golems, along with existing ones, are likely to be found early in the Neutrality Quest branch, around the golem level Sum of All.
Although the identity of the spellbook is randomized, the living lectern always uses the same magical attack: magic missiles.
One living lectern is guaranteed to appear in a ruined library at the top of the Lost Cities segment of the Neutrality Quest. There is a 25% chance of a second appearing there as well. In addition, 1d4 living lecterns are placed in waterlogged libraries.
Spell golems are able to cast spells.
A treasury golem may be thought of as a more advanced gold golem that contains precious stones as well.
A large number of treasury golems are found in the treasure rooms in Nessus.
When destroyed, argentum golems drop 1d3 stacks of 5d10 silver slingstones. In addition, they are generated with a silver dagger, which has a 1-in-6 chance of being replaced with a silver saber, and a large stack of silver arrows, which they will fire in volleys. Any silver arrows fired in this manner are destroyed.
Eight argentum golems appear in the Sum of All level of the Neutrality Quest.
To paraphrase a particularly wise prime, the rilmani are an
enigma cloaked in a riddle, wrapped in a mystery. Who can
question their motives or their actions? They keep their own
counsel. They're sworn never to come when called, but always
to be there when needed; never to answer questions put to
them, but always to provide what information is necessary; to
aid and abet good, evil, law, and chaos alike in order to maintain
the Balance, regardless of the cost or repercussions.
[ Planescape Monstrous Compendium II, by Rich Baker ]
Several unique monsters in dNetHack are golems: