Lantan
Lantan is an island nation from the Forgotten Realms. It has been part of the setting since the original 1E Forgotten Realms Campaign Set, which is still the main source for a lot of info on it. It's home to Gnomes (which are basically described as Tinker Gnomes, but competent) and a smaller number of Humans of Lantanna ethnicity (described as “ivory” to “parchment” skin with copper-red hair and large green or black eyes). These people live on rock pinnacles atop lush jungles that are connected by bridges. They worship Gond as their state religion, to the near exclusion of other deities. It is ruled by the Ayrorch, 12 people who serve for life on the council and select their own replacements.
What’s actually interesting about the place is that, instead of how Gnome "inventors" normally go, they’re actually successful at invention, totally ignoring the Medieval Stasis that infests the rest of the setting, possessing roughly Renaissance level of technology, with them having pistols (standard equipment for those hailing from there), early printing presses, coaches (not carriages, but their far more weight efficient successor), replaceable parts, and far more science fiction level devices. They have printing presses, but while 1E describes them as having violently stolen it from Halruaa, 3E describes them as built “under the auspices of Gond” and secret from the rest of the Sword Coast (which is retarded because printing presses had been described as operating openly on Faerûn in Realms of Valor, set 10 years prior to the 3E FRCS). Their ships are described as carrying “fire throwers” that fire fireballs, and explosive nets that act as mines. To reward them for hiding him during the Time of Troubles, Gond gave them Smokepowder, a comparatively, crappy, expensive version of blackpowder (Which Gond, contrary to his portfolio, prevents from working on Toril).
Their first mention says they have temples built primarily to serve foreigners, and that they are “energetic” traders with an official traveling government envoy. The 3E FRCS on the otherhand claims the rest of the world knows so little about them that Lantan is “half-mythical” and is wrongfully thought they shun magic, saying they only trade “occasionally” for materials like charcoal and glass (even though glassblowing anything bigger than a bottle is actually fairly high tech, with one piece glass windows not emerging till the Industrial Revolution), then contradicting itself by giving various inventions of theirs that have spread. This disparity would not be reconciled in 4E, as Lantan was destroyed like any other remotely interesting part of Toril in the Spellplague. 5E would retcon this, but merely say the majority of the islands were actually sent to Abeir and are now back instead of further detail the place.
Lantan has a semi-exclusive Prestige Class in 3.0 (and never updated to 3.5) via the book Magic of Faerûn. This class is titled "Lantanese artificer", which is just a rebranding of Gnome Artificer from the same book that requires Lantanese human instead of Gnome. The class is a mess. Just to qualify you need to be able to cast 1st level arcane illusion spells and have a bunch of different craft skills, but the class doesn’t advance casting. Instead of advancing casting, it gets its own pseudo-casting from a limited and largely lame list by being able to make magic item with relative ease and the (neat but too late) ability to turn magic items into stuff to build new magic items. The only real advantage this has over just continuing the class that got you casting in the first place is it doesn’t actually count as casting, and something with even worse casting (basically just Hexblade) can qualify.