Also;
Works of Thomas Aquinas
Regularis Concordia
Life of Saint Wilfred
Book of Armagh
Book of Nunnaminster
Periphyseon
Siege Engine Blueprints

Licenses to Crenellate and a variety of Bishop Croziers as priest only scepters coming in next patch.

For certain historical bishops which are rendered ingame as dukes. I may create character-locked versions instead.

I dont think i saw these two so i might suggest them:
The "Codex Gigas" also know as the "Devils Bible" : https://en.wikipedia.org/wiki/Codex_Gigas
And the "Codex Argenteus" aka the "Silver Bible" : https://en.wikipedia.org/wiki/Codex_Argenteus

Magna Carta
https://en.wikipedia.org/wiki/Irish_annals
~Assorted Classical Works

I would suggest:

The Book of Kells for Irish and Scottish culture characters
Boost Temple opinion and prestige
https://en.wikipedia.org/wiki/Book_of_Kells

De re militari (A Late Roman military text) for Catholic characters
Boost to Martial skill
https://en.wikipedia.org/wiki/De_re_militari

The Art of War as a Chinese artifact
Boost to Martial skill
https://en.wikipedia.org/wiki/The_Art_of_War

The Chronicle of Ireland
Boost to prestige and Temple opinion
https://en.wikipedia.org/wiki/Chronicle_of_Ireland

The Mabinogion for Welsh, Cornish, and Breton characters
https://en.wikipedia.org/wiki/Mabinogion

The Niblungenleid for German characters
https://en.wikipedia.org/wiki/Nibelungenlied

El Cantar de mio Cid (The Song of my Cid) for Castilian, Aragonese, Galician, and other Iberian cultures
https://en.wikipedia.org/wiki/Cantar_de_Mio_Cid

Summa Theologica for Catholic characters
https://en.wikipedia.org/wiki/Summa_Theologica

Historia Regum Britanniae for English, Welsh, and Scottish characters
https://en.wikipedia.org/wiki/Historia_Regum_Britanniae

Alexiad for Byzantine Characters
https://en.wikipedia.org/wiki/Alexiad

The Song of Roland for French and Norman characters
https://en.wikipedia.org/wiki/The_Song_of_Roland

Táin Bó Cúailnge (Cattle Raid of Cooley or just The Táin) for Irish characters
https://en.wikipedia.org/wiki/T%C3%A1in_B%C3%B3_C%C3%BAailnge

Sic et Non for Catholic characters
https://en.wikipedia.org/wiki/Sic_et_Non

Ecclesiastical History of the English People for Anglo-Saxon and English characters
https://en.wikipedia.org/wiki/Ecclesiastical_History_of_the_English_People

Beowulf for Anglo-Saxon characters
https://en.wikipedia.org/wiki/Beowulf

For artifacts other than books if you are interested:

Stone of Scone for Scottish characters (and perhaps the proud English usurper...)
https://en.wikipedia.org/wiki/Stone_of_Scone

Thanks for reading my long list. I will definitely subscribe.

Ohhh... Stone of Scone. I see you there. Nice idea. I think Art of War might actually be vanilla and Bede's Ecclesiatical History is already in there; it just doesn't spawn widely.

Book of Games for characters with the Game Master trait (or Scholar, which is what Alfonso X really was).
https://en.wikipedia.org/wiki/Libro_de_los_juegos

Here's the icon I'm currently using for it in my own WIP submod, feel free to use it with accreditation if you want:
https://i.imgur.com/AZP5nPy.png

Some examples of historically important books, many of them are still very well known and used:
Vitruvius's "De architectura" (discovered in 1486, it revolutionized engineering, architecture and other European arts, consolidating and refining the Renaissance)
"Corpus luris civilis" (Roman law, basis of all codes from Roman times to the present to civilized countries in Europe.)
"Lex Romana Visigothorum" (The most important Germanic law ever promulgated)
"Pactus Legis Salicae" (the salic law)
"Cantar de mio Cid"
Homerus's "Odyssea" and "Ilias"
Virgilius's "Aeneis"
Julius Caesar's "De bello Gallico" (a popular book among European princes and generals)
Saint Isidorus's "Etymologiarum libri viginti sive Origines"
"Chronicon Albeldense"
"Regula Sancti Benedicti" (The Rule of Saint Benedict)
Saint Augustinus's "Confessions"
Saint Thomas d'Aquino's "Summa theologiae"
Aristoteles's "Ars rhetorica", "Metaphysica" and "Ars poetica"

Ptolemy's Almagest / Syntaxis Mathematica / He Megale Syntaxis. 2nd Century Greek astronomical text.

Could be tied into the astronomy scholarship focus event chain somehow (ignoring that the event chain reaches the opposite conclusion - Earth goes around the Sun - to what the Almagest contains - Sun goes around the Earth. Details details...).

https://en.wikipedia.org/wiki/Almagest

al-Kafi, Bihar al-Anwar and Najhul Balagha

Najhul Balagha https://en.wikipedia.org/wiki/Nahj_al-Balagha
al-Kafi https://en.wikipedia.org/wiki/Kitab_al-Kafi
Bihar al-Anwar is too late for the timeline lmao, i just realised

Guide to the Perplexed, https://en.wikipedia.org/wiki/The_Guide_for_the_Perplexed

For Muslims/Lucifer's Own:
Kitab Asnam- https://en.wikipedia.org/wiki/Book_of_Idols
For Jews:
The Sword of Moses- https://en.wikipedia.org/wiki/The_Sword_of_Moses
Sefer HaRazim- https://en.wikipedia.org/wiki/Sefer_HaRazim
Maaseh Merkabeh- https://en.wikipedia.org/wiki/Maaseh_Merkabah
Sefer Raziel HaMalakh- https://en.wikipedia.org/wiki/Sefer_Raziel_HaMalakh
Sefer Yetzirah- https://en.wikipedia.org/wiki/Sefer_Yetzirah
Bahir- https://en.wikipedia.org/wiki/Bahir

Missing some books on Hermetica by Hermes Trismagistus

I suggest this works wich were some of the most important legally and culturally in Western Europe and Mediterranean:

For Iberians and Latin Group:
The Song of my Cid: https://en.wikipedia.org/wiki/Cantar_de_Mio_Cid
Ramon Llull's works: https://en.wikipedia.org/wiki/Ramon_Llull
Tirant lo Blanch: https://en.wikipedia.org/wiki/Tirant_lo_Blanch
Book of Deeds: https://en.wikipedia.org/wiki/Llibre_dels_fets
Forum Iudicum: https://en.wikipedia.org/wiki/Visigothic_Code

All the Mediterranean:
The Book of the Consulate of the Sea: https://en.wikipedia.org/wiki/Book_of_the_Consulate_of_the_Sea

Britain:
The diverse books from "The Matter of Brittain" (wich includes the King Arthur cycle): https://en.wikipedia.org/wiki/Matter_of_Britain

Love the mod a lot. The books part is amazing, but still needs some more balancing as their spam sometimes makes the stats way too high. But the artefacts works like charm.

Wanted to suggested some if you don't mind:

Banner:
Oriflamme (for the Frankish/French kings) https://en.wikipedia.org/wiki/Oriflamme

Regalia:
Holy Ampulla (for the Frankish/French kings) https://en.wikipedia.org/wiki/Holy_Ampulla
Reichskrone (for HRE emperors since the 11th century) https://en.wikipedia.org/wiki/Imperial_Crown_of_the_Holy_Roman_Empire
Throne of Charlemagne (for the city of Aachen)
https://en.wikipedia.org/wiki/Throne_of_Charlemagne
Reichskreuz (also for the city of Aachen) https://en.wikipedia.org/wiki/Imperial_Cross
Pluviale (for the kings of Sicily since the early 12th century; for the HRE emperors since 1194) https://de.wikipedia.org/wiki/Kr%C3%B6nungsmantel
Holy Crown of Hungary (for Hungarian kngs since the 11th century) https://en.wikipedia.org/wiki/Holy_Crown_of_Hungary
Corona Privilegiata (for the Polish kings since 11th century) https://en.wikipedia.org/wiki/Crown_of_Boles%C5%82aw_I_the_Brave
Crown of Zvonimir (for the Croatian kings since 11th century)
https://en.wikipedia.org/wiki/Crown_of_Zvonimir

Religious:
True Cross (for the patriarch of Jerusalem until 11th century and since 1099 - for the eventual kings of Jerusalem) https://en.wikipedia.org/wiki/True_Cross#Fatimids,_crusaders_and_loss_of_the_Cross

Books:
Coronation Gospels (probably for the city of Aachen as well) https://en.wikipedia.org/wiki/Vienna_Coronation_Gospels