Helpful links
RGSS
Ruby
Recommended Reading
https://forums.rpgmakerweb.com/index.php?threads/slip-into-ruby-an-introductory-guide-to-rgss-for-beginners.38900/ https://rpgmaker.net/articles/694/
Tutorials:
https://learnxinyminutes.com/docs/ruby/
Reference documentation:
RMXP: https://ruby-doc.org/core-1.8.6/
RMVXA: https://ruby-doc.org/stdlib-1.9.3/
Newest (mkxp-z): https://ruby-doc.org/core-3.0.0/