>>24806662 (OP)
/lit/ has one collaborative book in the Bavarian State Library (the Legacy of Totalitarianism in a Tundra, 1) and another in the Museum of Modern Art Library (Hypersphere, 2).
1.
https://mega.nz/file/fx9S0BAI#UYMjHrkmN03XkQWmbTygEqHJezgL5EkurxXrKb_wO-o
2.
https://mega.nz/file/Gk1kmCZB#cfEi3KNGgFZkVo6Oa6dIB52v8rRe4ZFb8YEBO3O7yw4
There have been various collab books on /lit/ (1), and various zines (2), more or less continuously since /lit/'s inception.
1.
https://mega.nz/folder/CoN2GbzQ#7puNpTNUTQ05QTha4H6-WA
2.
https://mega.nz/folder/2gsHSSbA#Sl46P4LljGlk9mnpAf3Mlw
One /lit/ magazine was a quarterly that released five issues and was paying anons on /lit/ $100 for accepted pieces (Lit Quarterly).
https://mega.nz/folder/fxN1ATyJ#xBD9BroJua0GysEvl71-Yw
Another magazine had over 30 issues across about two and a half years (the April Reader), which also had a small prize pool for one selected submission per release.
https://mega.nz/folder/TxkmCCbB#BZWdc1sDDsVVnfeWw0HYTw
There was also a best-of anthology (the best of &) that released about a year ago that drew writing from another /lit/ magazine, and of which two copies are owned by the photographer of pic related.
https://the-best-of-amp.github.io/
Currently there are two contests being run monthly, /lwc/ and /wibac/, where users write and vote/judge/critique. Those are compiled in books called the /lit/ Winners Club.
https://mega.nz/folder/usNllbQC#yWk55Mj355BvqwtUrfbYeg
I was partway through writing an article about these projects, but the /lit/ wiki got turned read-only in the middle of it.
https://lit.trainroll.xyz/wiki/Collaborative_Works