DemoScene

The DemoScene Archive has all of the demos that have ever come out.
https://www.scene.org

The Demo Scene Portal is THE page all about the DemoScene.
https://www.pouet.net

Music

Fast Tracker 2 is THE classic tracker.
https://www.pouet.net/prod.php?which=13350

Sound Club is a very old but exemplary music program.
http://www.bluemoon.ee/history/scdos

Renoise Tracker is the most modern tracker for Windows, Liunx and OSX.
https://www.renoise.com

MOD Archive is full of beautiful tracker music.
https://modarchive.org/

Tools

SubLime 3 Text Editor. The best source code editor I've ever seen. With syntax highliting for almost all programming languages, this tool is my first choice for daily program coding.
https://www.sublimetext.com/3

Code

SDL C ++ Framework is a protabele OpenGL library, not only for desktop systems, but also for Android and iOS. It houses modules for sound (e.g. .mp3, .OGG, all tracker modules, MIDI), graphic issues, network (e.g. TPC / IP) and much more.
https://www.libsdl.org

Tralala Music System is a Tracker Module player written in Pascal.
https://sourceforge.net/projects/tralala

People

People - Benjamin Rosseaux is a Pascal luminary
https://www.rosseaux.net/

Clean Code

This book by Robert C. Martin revolutionized my code style. I kept thinking: I've been programming for so many years, what is he telling me? Wrong thought! The suggestions in this book are worth their weight in gold.
at Amazon

3D graphics programming

The book by Marius Apetri is a unique work about the development of a software renderer. It not only shines with good code examples, but also with a complete mathematical background
at Amazon

Design patterns for game programming

Although the main feature is game programming, this book by Robert Nystrom is universally applicable. I find the work of the 'Gang of Four' much more cryptic, which is why I recommend this easy reading.
at Amazon

ARM 64-Bit Assembly Language

Nowadays ARM processors have become indispensable. Assembler is the basic building block of all software. Larry D. Pyeatt and William Ughetta's book is just the right resource.
at Amazon