There are 2 repositories under intellij-sdk topic.
Gradle plugin for building plugins for IntelliJ-based IDEs
Mirror of the IntelliJ SDK Docs Code Samples
Showcase for developing debugger tests using the CLion testing infrastructure in an external plugin
Плагин, упрощающий работу с аннотацией SideOnly
Unofficial IntelliJ SDK Code Samples that Might Not Fit Into the Main SDK Docs
IntelliJ plugin that simplifies the creation of Spring Boot projects with user customization