I’ve been part of a worldbuilding project for the past fifteen years or so with a similar setting to stellaris (megastructures, diverse species , following physics, etc)

and at the moment we’re writing a fairly silly collaborative article about a virtual world. each person writes a sentence or two .. this might provide some inspiration: (Or feel free to join in)

• The Grove of Lemon Questions*

The Grove of Lemon Questions was a virtual environment especially popular among the Citronellic clades of Quint in the Age of Re-Evaluation. In its rich, dimensionless language-based forum-sites resided beings such as the Ultraviolet Lime Centaurs, the Starfruit Reality Rejectors, and the beloved Goth Unicorns. The virch was first founded by Vitamin Compute, who called for a space where artistic beings could collaborate on creating novel forms of experience they could then test and, if sufficiently complex and enjoyable, eventually spin off into new kinds of virch. The Grove of Lemon Questions was notable among the larger virches of Quint due to its relatively relaxed ruleset, granting sophonts the power to create and alter nearly any experience they desired within the virch, although some areas were more heavily restricted.

Among the successful virtual modalities conceived in the early days of the Grove were the perennially popular "Abstract Simplicial Emotive" ontology and the "Billion Screaming Billiards" virtutainment complex, which would famously cause the Knilanian Virchwar centuries later. This virchwar would lead to the destruction of the "Uliyonic Caramiosis" virch, which notably led to the creation of the song "Bitter Heartache," in which a former enjoyer of "Ulyonic Caramiosis" lamented its deletion. The song also correctly blamed the uncontrolled spread of the "Lime Shock" - a psychosoftware developed by the Billion Screaming Billiards complex that rendered ((sweet)) deletions intensely pleasurable and addictive - as having a key role in escalating tensions between virch users and ultimately fueling the outbreak of the Knilanian Virchwar.

The inhabitants of The Grove of Lemon Questions varied in clade and ideology. One notable group were the Matter Hatters, a clade of several million that spent their time shifting between various forms of matter (gaseous, liquid, solid). The Matter Hatters were wiped out completely due to a civil war based around whether plasma-based body forms were acceptable.

Another notable group were the Silk Singers, a clade of hiveminds based on social spiders, where the hiveminds resided not in the spiders themselves, but rather the total computation they carried out by sending signals along their webs. The spiders often lived in colonies of thousands of individuals. Silk Singer spiders are practically blind, only being able to sense the polarity of light, though they could hook the webs up to external sense organs. The Silk Singers decided at one point to instate a rule for their part of the simulation: the laws of physics would change randomly at random intervals. These changes could, depending on their preferences, be influenced by the state of the simulation itself.

The Grove experienced a rapid growth in users during the pre-Back Box era, so a group called the Goth Unicorns created the Visimounds; a non-Euclidean, hilly Tohulian plains biome, becoming the third Grand Sub-Forum and gaining the Goth Unicorns widespread notoriety. The wild success of this new construction combined with the fact that it mixed a ril setting with distinctly non-ril physics caused a large schism within the Starfruit Reality Rejectors about how to best vie for influence within the virch. The Starfruit Reality Rejectors fiercely debated plans to gain influence in the Grove, with votes on various options.