This is a index of all the pages you will find from here that will help you get a headstart in this field along with some random but tricky stuff that even some professional find difficult and can't help to refer again from. Happy learning.
Finding your first bug Port Swigger Web Security Academy Nahamsec's beginner repo Hackers101 zonduus Bug Bounty Guide p4ndas so you wanna hack A blog on subdomain takeovers clos2100 on getting started without a technical background al-madjus from 0 to bug hunter dee-see's resources for Android Hacking
Broken Access Control Cryptographic Failure / Sensitive Data Exposure Injection Insure Design Security Misconfiguration Vulnerable and Outdated Component Identification and Authentication Failures Software and Data Integrity Failures Security Logging and Monitoring Failures Server-Side Request Forgery (SSRF)