Art in the imperium of man tended heavily towards either high religious culture, or lowbrow, highly censored mass media. While vast amounts of folktales, songs and low level visual art existed throughout the imperium it was very rare that these were transcribed beyond the planet they started out on, with only those with what the church deemed suitable being shared widely.
Within the Imperial church the decisions on what to make public, and what was heretical led to creatives regularly ending up being burnt alive, or at least censored to a high degree. Romance was a greatly censored topic, as was anything giving strength to the idea of individual satisfaction being something humans wanted.
The revelations of Saint Lin led to these restrictions being greatly lifted within the Imperial trust, and later, to a lesser degree, the dragons nest. While anything actually potentially chaotic was still clamped down upon incredibly hard suddenly individuals had a level of freedom to create rarely seen outside of backwater world's where Imperial rule was practically nominal.
This, along with the rise of literacy has led to a mass explosion in secular high culture. Whereas before musicians either sang praises to the emperor, or folksongs to a small audience now secular orchestras, bands and cogitator musicians (enabled by the technology found over Diepheobe) produced albums and symphonies of a class that hadn't been heard widely in over ten thousand years.
In addition, ancient music and stories, long deemed heretical was brought back into the fold. The archives of Muspellheim were a treasure trove for this, with a even few tales purported to have taken place before the birth of the emperor being found.
The average trust citizens were, for the most part, disinterested by this, but small communities of scholars especially on Muspellheim, Niflheim, and Averneus took to studying these ancient texts. The prize tales were a pair of long form poems, translated 3,000 years after the were written, detailing the tale of raiders attacking an ancient city, and the most cunning of these raiders journey home.
While theoretically, the communication with shapeshifting beings called gods was definitely heresy Lin carefully argued that as these tales were from before the rise of the emperor, it was in fact acceptable. He argued that these ancient people's moral system was as far from our own as is possible, and that as curiosities they were worth more than whatever tiny risk they posed.
In addition to the more ancient tales, millions of pages of literature were sifted through and translated by a vast delegation of pious priests Lin had sent to Muspellheim. Most of it was deemed harmless, and released to the public, while a few tales were put under very tight lockdown due to risks of depravity growing.
This rapidly growing body of work has been studied heavily by the academics of the trust, and several books have become widely popular, notably, the ancient English romantic tales by the ladies of house Brontë and Austin, and the detective tales of Conan-Doyle and Christie.
On top of the vast resovoir of fiction, philosophy and history, once almost forgotton concepts have once again began to thrive. While any philosophy going directly against the Imperial truth is still considered heretical, many dead ideas, such as empiricism, and logic, began to make a comeback. A few new philosophers have even arisen from the trust population.
The performance of ancient music, and pieces inspired by it however, has become enormous business in the trust. With the vast databases being analyzed carefully for memetic dangers by blessed cogitators, much of it again proved safe for public consumption, and has been publicised widely. Many of the once lost genres' have been revived, with strangely, an obscure one from the beginning of the dark age of technology named metal with a very high censorship rate becoming popular as bardic tunes on Asgard. It has been reasoned that this is because the knight pilots have already grown accustomed to its sound by the whirring of their chainsaws, though this statement was made by one of the Vanir, who almost entirely regard it as an artistic dead end.