So I'm making a D&D-style game...

[Quantum Goblin]

Anyone have any ideas for monsters or items? I've already got several "classic" monsters, but I want some more original/unique ideas.

[Tengu_temp]

The three questions you need to answer before making your own game:
1. What do I want to achieve with my game? What will be its defining element?
2. Isn't there another game out there that does the same thing better already?
3. Do I need to create a fully new game, or will homebrewing for an existing one be enough?

Starting with a list of monsters and items is rarely the best way to handle this.

[Eonas]

Read obscure fantasy and horror stories. Many of them are filled with interesting ideas which haven't been overdone to death.

I've found Mark's Adventure Glyphs an invaluable inspirational tool. If you completely clear your mind going into it, you can come up with some pretty original stuff.

Or, take three standard monsters, write down a list of 6 of their salient attributes, and roll a d6 on each of the three tables to come up with something interesting. For instance:

.	Lich	Werewolf	Goblin
1	Undead	Shapechanger	Small
2	Phylacteries	Howls at the moon	Cunning
3	Wizard	Infects others	Pack animal
4	Drains energy	Amnesia	Fragile
5	Overlord	Rageful	Lives underground
6	Depraved	Killed by silver	Hideous

I rolled 3d6 and got 4, 5, 1. I check against the various lists and find that my new monster Drains Energy, is rageful, and is small. So perhaps it's a tiny little monster that follows a particular person around and feeds off their anger. The more it feeds, the more it grows larger and stronger, and the more the stalkee is fed upon (and it can only feed the monster by being angry), the more it weakens and shrinks.

See? That was easy. I'm sure you can come up with far better, though.

[hemming]

The molecular chameleon - this brutish humanoid appears as a large wingless gargoyle; takes on the attributes of and gains DR to the last type of attack that hit it; dam output type shifts to last type of attack that hits

Clockwork bomber - these knee high automatons creep forward on six legs, holding a pot of alchemist fire clamped onto their backs. When wound with a key, clockwork bombers lurch forward in a straight line. On contact with an object, a small spring loaded mallet breaks open the fire pot and releases an area burst of alchemist fire

Gremlin - ferocious and feral, these lithe 3 foot tall carnivores are capable pack hunters. Though fairly intelligent, gremlin tribes tend to live far from other settlements, use little to no technology, and speak only in their own tongue. Adept climbers with the ability to cast Haste and Invisibility at will, gremlins are masters of setting deadly ambushes.

Smoke Elemental - similar to air elemental, but can only exist on material plane where there is a source of fire. Creatures caught in a smoke elemental make a fort save or act as stunned for one round