You can search for site by subject or level
[Culture] [Intermediate] Site search （3）
This is a site where you can learn Japanese comprehensively with tremendous content and manage your learning progress with Kanshudo AI.
The basics of Japanese are carefully explained here, making it a very useful site for people who are thinking about starting to learn Japanese, or for Japanese learners who have just begun their studies.
An audio-visual resource site designed by Tokyo Metropolitan University. There is an abundance of YouTube content, useful as well for those who study alone.