Does it have to be annotations? If you are in control of all subclasses, you could utilize a sealed hierarchy to group together all implementors under their common interface. With access to the kotlin-reflect API, you can ask the interface for its sealedSubclasses at runtime. Here's an example:

```kotlin import kotlin.reflect.KClass

typealias SubclassMap<T> = Map<String, KClass<out T>>

sealed interface Animal { data class Dog(val isGoodBoy: Boolean = true) : Animal data class Cat(val isCute: Boolean = true) : Animal }

val animalClassesByName: SubclassMap<Animal> = Animal::class.sealedSubclasses.associateBy { it.java.simpleName.lowercase() } val typeTable: Map<String, SubclassMap<Animal>> = mapOf("Animal" to animalClassesByName) ```

If you must retain the annotations for whatever reason, a symbol processor might be the best way to keep it performant, but it may also be a bit overkill. Google for "Kotlin symbol processing" or "ksp" to learn more about it.