OWASP Developer Guide
github.com
github.com
https://github.com/OWASP/DevGuide/blob/master/DevGuide3.0/03...
But they have become less and less relevant in recent years, rather than more relevant. Their previous work on the OWASP Testing Guide, and OWASP Developer Guide are excellent, but are becoming dated now; there are several efforts to bring this up to date.