Here is my personal favorite compilation of go-to links to learn and debug my pine scripts:
Learning roadmap
Pinecoders FAQ
A bit advanced level but contains a lot of good stuff:
Pinecoders Frequent Asked Questions
The Pine Reference Manual
The pine scripters bible - list all the built-in functions/variables specifications (how to use them, list of parameters, etc..)
Pinescript V4 specifications
Not much are aware this space even exists... that's a shame because we find loads of gems
Pinescript version 4 specifications
Kodify
Want to learn how to structure a pine program, write a strategy, and learn with one of the best pine tutorials out there?
Backtest Rookies
Another great website to learn pinescript - complementary to all the ones listed above