What happened Edition
General theory - http://www.dolmetsch.com/index.htm
Basic Theory and exercises
https://www.musictheory.net/
https://www.teoria.com/
General resources
Various files on advanced/abstract topics - http://www.pdmusic.org/theory.html
A lot of content geared towards college level music theory - http://openmusictheory.com/
Books
file:///E:/Music%20Theory/Books/Cowell_New_Musical_Resources.pdf
Video resources
Music Theory playlist by Christopher Brellochs that covers basic theory to more advanced topics - https://www.youtube.com/playlist?list=PLw9t0oA3fHkxx1PgYpiXrMUPXaOiwh6KU
Analysis of video game music, it’s not very sophisticated, rushed, and he can go more in depth in the music, but he still has good information to share - https://www.youtube.com/channel/UCeZLO2VgbZHeDcongKzzfOw
Explanations of music theory topics and some analysis on songs, same problems as previous channel but still useful - https://www.youtube.com/channel/UCTUtqcDkzw7bisadh6AOx5w
Some basic videos on this channel recommended for people who are just starting to learn theory - https://www.youtube.com/channel/UC8yI8P7Zi3yYTsypera-IQg
>keeping thread alive
Here is a theoretical idea I had that helps me compose music.
>Chord decomposition is the process of reducing the tones in a chord to a smaller state of the chord which only has 2-4 notes. For example if you wanted to decompose a E13#9 (E(1), G#(3), D(b7), F(#9), C#(13)) chord, one decomposition would be G#-C# combination. Others could be E-D, E-G#, E-C#, E-F, D-G#, D-C#, D-F, G#-F, C#-F. There are still more combinations, such as triads and 4-note chords to work with. Use these combinations like a melody or a chord progression to outline the larger chord they are based off from.