[Meo-Ada Mespotine]

Official docs by Cockos:
EEL2 reference manual
JSFX-Reference-manual
Theme-Development(Walter)
Custom Mousecursors
Extensions SDK
Extensions SDK for VST
OSC in Reaper
Langpack translation of Reaper
http://cockos.com/wdl/ - WDL for Reaper(helper functions for your extension-plugin)
https://www.reaper.fm/sdk/reapeaks.txt specs for the reapeaks-files
How to add support for embedded GUIs in your VST-plugin


As there are so many great tutorials done by the community, I should add them here as well:

Embrace everything by Kenny Gioia

programming in general:
https://forum.cockos.com/showthread.php?t=275747 - collection best practices
https://forum.cockos.com/showthread.php?t=275831 - discussion for optimizing ReaScript-code(for advanced scripters)

How to start programming ReaScripts:
https://www.extremraym.com/en/series...ipt-beginners/ X-Raym's tutorial-series
https://forum.cockos.com/showthread....05#post2774405 - Tutorial video series by Daniel Lumertz

Stretch Markers ReaScript tutorial by X-Raym

How2Send SysEx-Messages from script

Python and Reaper by dimentorium

How to write JSFX-Plugins:
https://wiki.cockos.com/wiki/index.p...sonic_Tutorial by Loser
https://forum.cockos.com/showpost.ph...3&postcount=90 how do jsfx work internally by mschnell
https://forum.cockos.com/showthread....31#post2357031 - Video tutorial series by leafac
https://forum.cockos.com/showthread.php?t=270821 - advanced JSFX programming by Jack461

About bitwise operators(&& || OR AND)

GUI/gfx-related:
https://forum.cockos.com/showthread.php?t=176662 lokasenna's "how to create a gui"-tutorial
https://forum.cockos.com/showthread.php?t=161557 useful gfx-snippets by spk77

C/C++ Extension Plugins related:
How to create a multiplatform extensionplugin? by Argitoth
Hello World-Demo-Plugin by Chris Fillion
Hello World-extension-template with VSCode+CMake by en5ca
How to make embeddable Plugins - thread


Theming with Walter:
https://forum.cockos.com/showthread.php?t=69767 Tutorial by WhiteTie

ReaperTheme colors by Amagalma

Accessibility-ressources, listed by Scottsdale:
https://forums.cockos.com/showpost.p...45&postcount=8

Statechunk-documentation

Lua:
https://www.youtube.com/watch?v=S4eNl1rA1Ns - Learn Lua in one hour (not from the community, but I learned Lua with Tyler Neylon's great tutorial)

If you know more, please leave a link in this thread