There are many websites that offer free knowledge on a variety of topics, including education, technology, courses, and more. These websites can be a great resource for students, professionals, and anyone else who is looking to learn new things.

Here are a few of the most popular free knowledge websites:

• MIT OpenCourseWare (ocw.mit.edu)
• Code.org (code.org)
• Mozilla Developer Network (developer.mozilla.org)
• Google Developers (developers.google.com)
• GitHub Learning Lab (lab.github.com)
• Microsoft Learn (learn.microsoft.com)
• Creative Commons (creativecommons.org)
• Stanford Online (online.stanford.edu)
• Harvard Online Learning (online-learning.harvard.edu)
• OpenClassrooms (openclassrooms.com)
• Treehouse (teamtreehouse.com)
• The Code Player (thecodeplayer.com)
• Java Tutorials by Oracle (docs.oracle.com/javase/tutorial)
• CodeHS (codehs.com)
• Google AI Education (ai.google/education)
• IBM Developer (developer.ibm.com)
• TheNewBoston (thenewboston.com)