If you chat to a straw golem, it will say a random strawman argument, e.g. “If the priests give two bits to every beggar, nobody will want to work anymore.” or “The straw golem completely misrepresents your argument.”

Cursed boots that you have worn for at least 300 turns should emit a stinking cloud when finally removed.

Demon cartographers (not specified if this would be a new monster species or just the occasional random peaceful monster of an existing species) who offer to sell you scrolls of magic mapping for exorbitant prices.

Blade vortex (v), which is a whirlwind of spinning blades. It has two engulf attacks that deal 2d4 physical damage each, and is difficulty 12. Apart from generating normally, it can be created by polypiling a sufficiently high number of blades at once similar to how golems are created. When killed, it drops an assortment of bladed weapons, mostly smaller ones like knives, daggers, and short swords, and possibly a chain or two. It can be harmed by thrown potions of water, rust traps, and rust attacks.

Another iteration of the proposal is to make its blades its inventory rather than just assumed to be part of the monster, with the following interesting implications:

• Rather than just the monster dealing damage, it actually makes attacks with randomly selected weapons against an engulfee, which could do things like silver damage if the vortex has silver weapons whirling around inside it.
• Could have 6 attacks, each of which must use a different weapon. (If it only has 3 weapons in its inventory, it only gets 3 attacks.)
• It would also have to generate with an inventory of a few blades, selected randomly from the set of bladed weapons under a certain weight (no giant battle-axes).
• If it passes over blades lying on the ground, those are sucked into its inventory (which would make it even more deadly if it attacks with weapons it holds).
• Also, hitting it with thrown blades will result in those blades being sucked in (and possibly dealing no damage since it’s obviously not harmed by its own blades).

Displacer beasts could drop their hide, which can be enchanted or otherwise crafted into a cloak of displacement.

You can get some rare intrinsics by eating artifacts that confer them. For instance, eating Excalibur could give level-drain resistance, or eating Grayswandir could give hallucination resistance.

The chance would be much less than 100%, possibly even lower than the standard odds of getting an intrinsic from eating jewelry.

A more in depth stealth mechanic. Involving hiding in containers, possibly on the ceiling if you can levitate, making monsters behave as if they can’t see you even in line of sight, creating illusions or using displacement to make diversions.