The following is a brief introduction to the region of space around the World of Enzada, and the subject of discovery and exploration for (of all systems) the OSE game I am running. Right now they're still on Enzada, for the most part, but they are on the cusp of moving on to a much more rigorous space adventure.
An Introduction to the Dreadfire Nebula Expanse
The mysteries of the galactic civilizations around the world of Enzada start with a region called the Dreadfire Nebula Expanse, which includes the Commonwealth, a coalition of independent worlds that united under a sort of "United Planets" charter to provide common protection and civil services across dozens of colonies. The main hub of activity is in the Seven Pillars region, a part of the Nebula known for spectacular gaseous formations called the Seven Pillars, where a dozen or so planets are the center of trade and commerce. Spinward from the Commonwealth is the Border Sector, where mostly independent colonies and free worlds can be found. Beyond that is the Hexen Expanse, a vast sector of unclaimed territory that used to be comprised of the Aon Empire, which collapsed about a century ago due to internal civil war, and left a vast swathe of unclaimed and uninhabited worlds in its wake, many devastated by the necrophage virus which was believed to be a superweapon that got loose.
A noteworthy mysterious region of the Dreadfire Nebula is known commonly as the Hub System, and is one of many worlds stretching deep into the heart of the sector that show evidence of the ancient race called the Shapers, going back at least one million years. The "greys" can be found here, or evidence of their remains, often on abandoned orbital stations. They are believed by some to be genetic descendants of the original shapers. The people on the mainworld (Enzada) call the Shapers the Sky Builders in their local beliefs. Enzada is one of a handful of worlds classified as "Anomalous" in the Shaper worlds of the region, as each one exhibits unique properties due to ancient Shaper technology that warps local physics in strange ways, allowing for what is known as magic to prevail. Magic is different from psionics in subtle ways, and considered more powerful, as it messes with higher-dimensional quantum states but is influenced by psionics and the lost technology of the Shapers. Beyond that, not much is understood about Shaper worlds, as most are considered off-limits by the Commonwealth except for academic study, and Commonwealth rules do not allow advanced technology to be placed in the hands of pre-stellar civilizations that are not ready to join the galactic community. Uplifting a pre-stellar world is considered a high crime in the Commonwealth.
The one colony in Hub System is known as Academy-992 on the dwarf planet Ceremos, a way station and academic center run by the Commonwealth Scientific Academy of Research and Discovery (CoSARD). It's been there for three centuries now, since before it was a research station and was just a freeworlds port, and was previously dominated by salvagers and relic hunters until the authorities took it over about eighty years ago. The Commonwealth didn't grow into its current state until the Aon Empire collapsed, but on inheritng swathes of unclaimed territory once held by the Aon Empire, the Shaper Worlds posed a conundrum. The mystery of why the Aon Empire regarded the Shaper Worlds as off-limits has not been revealed, and the Commonwealth authorities decided to hold the same restriction, but with limited academic study, to see if they could figure out what the Aon Empire knew that they don't. Academy-992 on Ceremos caters to this careful research, and also still allows for local belter mining and relic hunting, but only on the ruins of salvageable relics, stations and artifacts on the other uninhabited worlds of the system, or the derelict orbital platforms around Enzada (of which there are 136 considered “fair game.”)
Five orbital stations are classified Anomalous-High Risk, and each contains what appears to be a manifestation, possibly pan-dimensional, of the anomalies locals call the Star Gods. These interstellar beings are difficult to approach and study, and appear to have exerted some influence on the religious beliefs of the world below. Only a few other planets in the galaxy have such creatures present, and researchers are convinced they are either higher-dimensional entities partially manifesting in our lower dimensional spaces, or are much older than anyone can imagine, possibly being precursor species that predate the age of the current Universe; the end product of post-Kardashev Type III civilizations that survived the collapse and rebirth of a prior universe. Either way, they are considered off limits to approach and all attempts at contact have been fatal.
Last Item of note is that the center of the Dreadfire Nebula is an immense star-cluster known as the Maelstrom, where a gigantic black hole is in the process of ripping apart a trinary star system. The dense cluster of stars is where the old empire's secret shipyards are believed to have been stationed, along with their top-secret weapons program. Multiple powers in this region of the galaxy are interested in finding this vestige of the empire if they can; and it is ostensibly part of the "Shaper Anomalies" so doing so requires Commonwealth approval or going rogue.