OWASP Juice Shop: Probably the most modern and sophisticated insecure web application
OWASP Mutillidae II is a free, open-source, deliberately vulnerable web application providing a target for web-security training. This is an easy-to-use web hacking environment designed for labs, security enthusiasts, classrooms, CTF, and vulnerability assessment tool targets.
OWASP API Security Project
Secure PHP Development — lab-driven study notes: modern PHP 8.2/8.3 through a full OWASP-mapped catalogue of PHP vulnerabilities with exploit-then-fix labs. CC BY 4.0.
A lab-driven course on breaking web applications and explaining how to fix them — 491 notes, 36 reproducible labs, mapped to OWASP WSTG and the PortSwigger Top 10 Web Hacking Techniques.