D&D General what is the unifying theme of gnomes?

[Bupp]

On my World of Eska, forest gnomes are the stereotypical red pointy hat wearers.
There was an OSR or 3rd party 3.x book that I can't remember the name of, but had an awesome cover of some badass looking forest gnomes. Bonus points to anyone who could ID it.

My rock gnomes = jawas from Star Wars. Roaming clans of scrappers and craftsmen. They are the creators of the warforged.

 

[MichaelSomething]

Gnomes have no idenity; that's the great part! The DM is free to give them whatever identity that suits their needs without players saying it clashes with some preexisting book.

 

[Nebulous]

In real world occultism, gnomes are one of many names for faeries or earth elementals. They exist in the astral, and are generally invisible except to certain clairvoyants, but even then they do not have a distinct shape, seeming to form themselves from what the clairvoyant might imagine them to look like.