Here is a list of all modules:
[detail level 123456]
 BoardsBoard specific definitions and implementations
 BootloadersApplications that facilitate the startup process in presence of upgradable firmware
 C++C++ Support in RIOT-OS
 CPUCPU specific implementations
 Compile time configurationsList of compile-time configurations
 DriversDrivers for external devices as radios, sensors, memory etc
 ESP32x CommonDefinitions and configurations that are common for all ESP32 boards
 Generic pseudomodulesModules influencing general RIOT behavior
 KernelThe RIOT micro-kernel containing the core functionality
 NetworkingNetworking libraries
 PackagesExternal libraries and applications
 SystemSystem library contains tools and utilities that make RIOT an actual operating system
 UtilitiesUtilities and helper functionality