Art of Anti Detection 3 – Shellcode Alchemy

Part 1 is also good, it gives a great explanation of anti-virus techniques.

https://pentest.blog/art-of-anti-detection-1-introduction-to...

While I'm commenting, I'll also say that I found this article from "Inside Security" newsletter, which I find to have consistently interesting stuff I don't find elsewhere (I'll admit I am not on every security newsletter).