Coolest Monsters Introduced After the 1e Era

[Shasarak]

Warforged are a great new monster type added since 1e.

 

[Jhaelen]

I liked a lot of the original 2e Dark Sun monsters. It's amazing how much more interesting a monster becomes if it's intelligent and has a bunch of thematic psi powers.
The 'Druj' from the Mystara setting also stood out to me: a kind of spirit animating body parts.

3e also had a bunch of memorable monsters:
- In MM2 there was the Teratomorph, a gigantic ooze that warped reality and ripped holes into the structure of the multiverse.
- Also from MM2, the Zodar were a race of mysterious, incredibly powerful beings encased in obsidian armor.
- In MM5 there's the Rylkar, a race of evil giant rats, controlled by an extra-large, bloated mother rat called 'Harridan'.
- Also from MM5, Siege Beetles are simply gargantuan beetles, but they're actually worse than the dreaded Tarrasque, especially since they can fly...
- Finally, there's 'Illurien of the Myriad Glimpses' from MM5, a unique being roaming the Outlands that is basically 'living knowledge'.

 

[Richards]

3e also had a bunch of memorable monsters:

...Also from MM2, the Zodar were a race of mysterious, incredibly powerful beings encased in obsidian armor.

The zodar actually date back to AD&D 2nd edition. There's a Spelljammer Monstrous Compendium (back when they were hole-punched pages you added to your binder) with details on the zodar.

Johnathan

 

[Kaodi]

Quori were pretty cool, as I recall. I do not think they quite escaped the orbit of their setting though. Just like draconians never really escaped until, sort of, dragonborn.

 

[Jhaelen]

The zodar actually date back to AD&D 2nd edition. There's a Spelljammer Monstrous Compendium (back when they were hole-punched pages you added to your binder) with details on the zodar.

You're right, of course. This reminds me of another (group of) monster(s) from the 2e Spelljammer MC that I thought was really cool: the Witchlight Marauder(s):

Witchlight marauders are terrors that can lay waste to an entire planet, leaving nothing but barren rock and briny seas. Marauders can digest animal and vegetable matter, as well as metal and precious minerals—but not bare rock. They often strip the land down to bedrock before moving on. Marauders excrete a dark sludge that reeks of burning tar and supports no life. Their insatiable hunger can devour all life on a world in a few year's time if left unchecked.

Witchlight marauders were introduced by the orcs during the first Unhuman War. Thought to be completely destroyed by the elves before these living weapons could be used, rumors and legends persist that several primary marauders were preserved.

When released upon a planet, a primary marauder will "forage" for several weeks before establishing a lair. This lair is often guarded by secondary marauders. After a few days the primary will split like an amoeba into two primary marauders of minimum hit dice. This cycle continues until the marauders run out of food, whereupon they turn on and destroy each other.

Space witchlight marauders are enormous creatures—over 1000 feet long—that are the source of planet-killing primary marauders. These spacebourne monstrosities fly through the void on web-like sails they spin. Their crocodilian mouths are several hundred feet long and full of thousands of sharp teeth. Their heads are dotted with small, red eyes; and they have six tentacles—each capped with a huge mouth—ringing their necks. The space marauders "tail" is mass of writhing tentacles protecting a handful of umbilicals, at the ends of which grow primary witchlight marauders or "remote" feeders—flying gullets that gather additional nourishment for their parent.

To help it feed, the space marauder can release a group "remote" feeders, and is often accompanied by 2-5 of these ravenous maws.