A Neo-Transcendentalist was an individual who followed the philosophical movement founded by Liam Dieghan on Earth in the early 22nd century. These adherents advocated a return to less technological driven lifestyles with an emphasis on self-reliance and nature.
The SS Mariposa, a colony ship launched from Earth in 2123, carried a group of Neo-Transcendentalists who eventually settled on Bringloid V. (TNG: "Up The Long Ladder")
This general philosophy resonated on into the 23rd century, as was the case of the Omicron colony and the Luddite collective in which Joann Owosekun was raised, and into the 24th century, with vibrant followers being Alixus and other influential scientists on Earth. (DIS: "New Eden"; TOS: "This Side of Paradise"; DS9: "Paradise")
These latter examples were not so-described by name, but follow in the same vein of the philosophy.