Literature

Scrolls are the main literature of Pyrrhia, written and read by almost all of the dragon tribes. They are printed with ink on an unknown variant of paper, likely vellum, as heavily hinted by Starflight in The Dark Secret.

Tribes

MudWings - In The Dark Secret, Pheasant said she was reading about the Prophecy, hinting that MudWings sometimes read scrolls. This is also shown in Moon Rising when Sora is reading in the library. In The Brightest Night, Queen Moorhen mentions how she has read Queen Coral's scrolls before, giving more evidence of literacy in MudWings.

SandWings - Thorn of the Outclaws has been shown writing Wanted posters, and these are likely scrolls or made from the same material as scrolls since it seems the only papers are scrolls. Also, Smolder intercepts messages written on scrolls, and it can be assumed that most SandWings read scrolls. In The Brightest Night, they also went into a letter room where there could have been sent scrolls. 

SkyWings - Peril lied to Scarlet about reading about the Champion's Shield in a scroll, and Queen Scarlet replied, saying "with claws that burn through paper right when you touch it", which reveals that SkyWings read scrolls and that the SkyWing queen knew Osprey had told her about it. They also use scrolls for messaging.

SeaWings - The SeaWings read scrolls, most of them written by Queen Coral. Some of her work includes The Missing Princess, The Tragedy of Orca, The Claws of Murder, A Tail of Blood, and many other stories, all of which are taught in SeaWing schools. The scrolls are written with a mixture of squid ink and a little whale blood, created by Whirlpool, to make the words not fade.

RainWings - RainWings didn't read scrolls and never knew about them or the rest of Pyrrhia until Glory claimed the throne. In The Dark Secret, Sunny was teaching a dragonet class how to read, and in Winter Turning, Kinkajou went to a nearby school to get some paper and a blank scroll for Moonwatcher to draw and record her visions on.

IceWings - Winter explains in Winter Turning that his mother made him memorize stories of dragons attempting the Diamond Trial, revealing that IceWings can read. He also mentions IceWing sagas that supposedly "told the history of the world."

NightWings - The NightWings read scrolls and wrote many of them, and Starflight and Mastermind have always been fascinated by them. There used to be a large library at the Night Kingdom.

List of Known Scrolls

The Tragedy of Orca - Queen Coral's first scroll about her daughter, Orca.

The Missing Princess - A scroll written about Tsunami's egg's disappearance.

The Claws of Murder - Mentioned by Blister, likely a murder mystery.

A Tail of Blood - Another one mentioned by Blister, also probably a murder mystery.

Tales of the NightWings - A scroll with lots of stories about the NightWings' greatness.

A NightWing Guide to the Dragons of Pyrrhia - The guide of the Pyrrhian dragon tribes including drawings and descriptions. The scroll has incorrect information on RainWings.

A Longitudinal Study of Peculiar Scavenger Behaviour - A scroll about Scavenger life on Pyrrhia.

Dangers of the Rainforest - A scroll about the dangerous animals and obstacles of the Rainforest Kingdom.

A Natural History of Unnatural Dragon Abilities - A scroll mentioned by Starflight about strange abilities of dragons.

Where are the Dragonets of Destiny? - A scroll listing theories about who and where the dragonets were.

War of SandWing Succession - A scroll about the SandWing war.

Animus History - A scroll read by Moonwatcher about animus dragons and their enchanted objects.

The Royal Lineage of SeaWings, from the Scorching to Present - A scroll about SeaWing Royal Lineage

Geography of Pyrrhia - A scroll owned by Darkstalker, presuambly about the continents kingdoms and landscape.

Ancient Wars of Pyrrhia - A scroll owned by Darkstalker about old Pyrrhian wars. The NightWing uses his magic to make the book talk like Truthfinder.

Ten Little Scavengers (Recipies Included!) - A scroll owned by Darkstalker, most likley a book for younger readers.

Goodnight, Moons - A scroll owned by Darkstalker (also a joke about real-life lullaby story, Goodnight Moon)

Myths of the Lost Continent - A scroll owned by Darkstalker about  the fairy tale of the Lost Continent, which is now revealed not a fairy tale but a actual place.

Legend of the Hive - A scroll Hope mentions in the RainWing village, presumably about Pantala.

Mentioned Scrolls

• In The Hidden Kingdom, Glory mentions a scroll about a blind dragon that dated back before the Scorching.
• Glory also mentions a scroll about electric eels in The Lost Heir.
• In The Dark Secret, Starflight reads a scroll about two NightWing authors debating whether to kill all the RainWings or enslave them.
• Clay mentions a scroll called The Sluglike Qualities of MudWings in The Dragonet Prophecy.
• In Darkness of Dragons, an old RainWing scroll in the library of Possibility is mentioned. It is likely it contained valuable information since Moonwatcher jumped up and down when she saw it.

Trivia

• A NightWing Guide to the Dragons of Pyrrhia was once called 'The NightWing Guide to the Tribes' by Starflight.
• It is unknown whether or not The Sluglike Qualities of MudWings is a joke or a real scroll.