The Ba'ku are a bunch of nauseating, self-righteous, technology-hating Wholesome Small-Town Folksy People in Star Trek: Insurrection. They inhabit a planet of the same name in an area of space known as the Briar Patch, where abundant metaphasic radiation allows them to live lives free from the burdens of disease and aging (after reaching adulthood). Yet they apparently didn't feel the need to share their great discovery with the rest of the Alpha Quadrant.
Their attitudes are very technophobic, which -- according to Hollywood logic -- automatically means a perfect idealized lifestyle. They claim to believe that "If you build a machine to do the work of a man you take something away from that man." One major thing of note about their village is that up stream of it is a massive concrete dam that they supposedly built, regardless of how impossible it would be for a population of only a few hundred to even start to construct such a massive structure. The dam also includes machinery for raising and lowering the spillways (which are made of huge steel plates that a hand-forge could not possibly produce), in direct violation of their own preachy nonsense.
At one point, a group of them chose to leave the planet and became exiles known as the Son'a. Forbidden to return, the Son'a began to age and suffer diseases like other humanoids, so they schemed to steal the "metaphasic particles" from those who had exiled them.
The Ba'ku population is tiny, consisting of only a few hundred known members. While their governance isn't defined, some kind of communal, participatory democracy seems likely.
The Ba'ku are pacifists, so they present no threat to other civilizations. They appear to be familiar with advanced 24th-century technology, but unwilling to use it. Their tiny population means that a platoon of well armed soldiers could easily defeat them.