A handful of go books and other content have been released under Creative Commons licenses. Below is a catalog of those that I am aware of. This post is a wiki, which can be edited freely. Please add more that you know of.
Books
Shape Up!
- by Charles Matthews and Seong-June Kim
- Download: https://cdn.online-go.com/shape_up_v1.2.pdf
- Other info: OGS is proud to host Shape Up!, Shape Up! book update
- License: CC BY-SA 4.0
81 Little Lions: An Introduction to the 9x9 Board for Advanced Beginners
- by Immanuel deVillers
- Download: 81 Little Lions: An Introduction to the 9x9 Board for Advanced Beginners, by Immanuel deVillers — Revised Edition (2019)
- Other info: 81 Little Lions - An introduction to the 9x9 board for advanced beginners
- License: CC BY-NC-ND 4.0
Relentless: Lee Sedol vs Gu Li
- by Younggil An, Josh Hoak, and David Ormerod
- Download: https://archive.org/details/relentless_201607
- Other info: https://www.goodreads.com/book/show/29891040-relentless, https://www.reddit.com/r/baduk/comments/4ms0vu/update_on_relentless_ebook/
- License: CC BY-NC-SA 4.0
Websites, Interactive Content
Learn to Play Go Already!
- by AdamR, Lucas Westerman, Kosh, Joshua Batson
- Website: https://www.learn-go.net/
- Download: https://gitlab.com/Adam314159/hugo-ltpg
- License: CC BY-NC 4.0
Problem (Tsumego) Collections
GoGameGuru’s Go Problems
- by GoGameGuru (Younggil An and David Ormerod)
- Download: https://github.com/gogameguru/go-problems
- License: CC BY-NC-SA 4.0
Commented Games
GoGameGuru’s Commented Go Games
- by GoGameGuru (Younggil An and David Ormerod)
- Download: https://github.com/gogameguru/commented-go-games
- License: CC BY-NC-SA 4.0
Images, Graphical Assets
go-assets: various resources (i.e. images) related to the board game ‘Go’
- by Andreas Tarnowsky
- Download: https://github.com/atarnowsky/go-assets
- License: CC BY-SA 4.0
Go Equipment and Trebuchet Photos
- by yebellz
- Download: Go memes!, Go memes!, Show your Goban/Study Space!
- License: CC BY-NC-SA 4.0
Software and Libraries
Software is generally not released under Creative Commons licenses, since these licenses are not designed for software and might not be most compatible with the aims of free, open-source software projects. In fact, the Creative Commons discourages it for those reasons.
However, a list of free, open-source software/libraries (generally under various other licenses) related to go can be found here: