Here's where those dropdown entries are defined: https://github.com/JetBrains/intellij-community/blob/943aadf32547ef82df3690e6ee8e549cebd3b2f0/plugins/kotlin/project-wizard/core/src/org/jetbrains/kotlin/tools/projectWizard/moduleConfigurators/ModuleConfiguratorWithTests.kt#L134-L185 The reason those are in the list is because they're the only JVM test plugins bundled with intellij. So unless you can convince JB to bundle the kotest plugin, I don't think you'll be able to add it to the dropdown.

Makes sense

It could detect if the kotest plugin is installed and offer that option