The Thubanir are a neutral trading race found almost anywhere in the Alpha and Beta Quadrants. They grow cloaks while outside their own ships that they shed when returning.
Jean-Luc Picard became one of the few people to see a Thubanir without its cloak in 2371.
Thubanir count a person's experience by the number of times one dies, for they have the capability to regenerate after death even if only a single strand of DNA remains. There were problems at the Thubanir's first contact with other races until they were made to understand death was permanent for most species. (TNG novel: Intellivore; TNG comic: Ill Wind)
The Thubanir may have been affiliated with, or part of, the Lalairu collective of species.