Deep gnome

 In Golarion proper, deep gnomes serve as the only remotely (true neutral) approachable faction in the darklands. If you, however, do not play in Golarion, you might find a different niche for them, and with little to make them mechanically interesting (decent illusory disguise on scouts and warriors, and some more primal spells on the rockwardens), I'd say you should weave a story that makes them feel different.

Young gnomes have been disappearing from the city of Calora. An investigation of the metropolis's sewers - along with several encounters with enraged duergar - lead the gnomes' chosen champions deep underground, where a settlement of stone-skinned gnomes is built around a magitechnological contraption. The kidnapped gnomes are thrown into the machine's reservoirs, where long tubes pierce their flesh, and start drawing out all colour from their bodies. The machine then produces a nectar that is both invigorating and highly addictive for the deep gnomes. While the sages of the settlement are open to alternative fuels for the machine (which inevitably kills the captives), unless such an alternative is presented, they are not willing to stop the operation. Of course, violence is always an option, but the potion makes deep gnomes a serious force, not to be taken lightly...

Diddlyfrumph Cloisterdoinks was a moody old gnome who owned a tavern. The tavern was notorious for having a (heavily enforced) sign on its entrance that said "Entry forbidden to dogs and dwarves". When Diddlyfrumph dies of old age, his proteges find that he left behind a large quantity of face and hair paint, as well as a map that supposedly leads to a hidden treasure. There's only one problem - the map claims that the planet is hollow, and saying that out loud, or trying to prove it, is heresy in the eyes of the Smiling God and his powerful clergy...

After searching for it for years, a group of adventurers have finally found the fabled Bottomless Pit. Throwing his lamp inside is the only way to truly contain a djinn prince that the group have been dealing with since the humble beginnings of their epic travels. The only problem is, the only way to the pit is through a Svirfneblin temple-city. The gnomish men are willing to allow the adventurers to pass - but the dwarven princess in their escort must not set foot on the holy stone of the city. While the Svirfneblin swear on their forgotten gods' names that no harm will come to the princess, the demon who hides in her soul is sure to be let loose if but one deep gnome tries to draw blood from the girl. If its anger is unleashed, not only would the temple be razed to the ground, but the adventurers could end up with no way home...