If you have something you'd like to share in a language other than English feel free to post it.
I'll also continue to update this post if I ever discover another work to share or unearth some I've lost.
EDIT: shojo/josei link https://www.mangaupdates.com/showtopic.php?tid=130392&page=1#post792523
shounen/seinen link https://www.mangaupdates.com/showtopic.php?tid=130402&page=1#post792551

For yuri I'd suggest going to yuricon.com, a website dedicated to yuri content. From yuri mangaka interviews to articles discussing the tropes that have stood the test of time, you'll probably find it there. https://www.yuricon.com/essays/

Articles
Over at comicsforum.org we've got Manga Studies #4: Traversing Art and Manga: Ishiko Junzō’s Writings on Manga/Gekiga by Shige (CJ) Suzuki https://comicsforum.org/2014/08/11/manga-studies-4-traversing-art-and-manga-ishiko-junzos-writings-on-mangagekiga-by-shige-cj-suzuki/
whatismanga.wordpress.com gives us Are Yon-Koma Manga Comic Strips? https://whatismanga.wordpress.com/2013/05/20/12-are-yon-koma-manga-comic-strips/
Here we have a database for Osamu Tezuka's star system; a way he treated certain recurring, story hopping characters as actors that he even created imaginary salaries for. http://tezukainenglish.com/wp/?page_id=912

Books and Journals
One Thousand Years of Manga by Brig Koyama Richard begins not with manga itself but instead older Japanese visual art practices, such as picture scrolls that narrated tales.
Drawing From Memory by Allen Say is an art centric memoir whose author, in his youth, apprenticed with Noro Shinpei.
Mechademia: An Annual Forum for Anime, Manga and the Fan Arts is a journal by University of Minnesota Press (each year's issues get combined into book volumes) and as of right now vol. 4 is free online. https://muse.jhu.edu/issue/19533
Manga: An Anthology of Global and Cultural Perspectives edited by Toni Johnson-Woods


Essays/Theses/Journal Entries/ETC.
G. M. Shum's The Evolution of the Comic Panel in Japanese Manga To download it from the website click scholarsbank.uoregon.edu https://www.semanticscholar.org/paper/The-Evolution-of-the-Comic-Panel-in-Japanese-Manga-Shum/4c59d7623457e46b9f937bbd77dd2bf881713746
Kate Allen & John E. Ingulsrud's Manga Literacy: Popular Culture and the Reading Habits of Japanese College Students https://www.jstor.org/stable/40017172

Last edited by Enuj at 9:35 am, May 6 2022

Fredrik Knudsen did a good two part series explaining how manga and anime came to be: https://yewtu.be/watch?v=zZsFQPdU2dw
https://yewtu.be/watch?v=brF1zVXG5_0

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