AutoFabric

Currently, AutoFabric has one simple feature:

@Entrypoint("main")
class MyMod implements ModInitializer {
 // [...]
}

This will generate an entrypoint in your fabric.mod.json, for MyMod, with the type main, so you don't need to specify it yourself.
Obviously, any arbitrary value for EntryPoint, such as client or server will work.

Gradle

Add AutoFabric as a gradle plugin:

plugins {
    // [...]
    id "com.github.fudge.autofabric" version "1.1.1"
}

Despite being quite a complex arrangement, involving a Gradle plugin, annotation processor, and a compile-time dependency, you only need to add the plugin. Magic!

If you're using Kotlin, don't forget to add kapt to your project. The AutoFabric plugin will handle the rest.

plugins {
    // [...]
    id "org.jetbrains.kotlin.jvm" version "1.3.72"
    id "org.jetbrains.kotlin.kapt" version "1.3.72"
}

Entrypoints

You can also specify entrypoints for fields, methods, and kotlin Objects:

// Field
class MyMod implements ModInitializer {
     @Entrypoint("main")
     public static final Instance = new MyMod();
    // [...]
}
// Method
@Entrypoint("main")
public static void myInitializer() {
    // [...]
}

// object
@Entrypoint("main")
object MyMod : ModInitializer {
    // [...]
}

You can specify multiple entrypoints for a single target as well.

@Entrypoint({"main", "client"})
class MyMod implements ModInitializer, ClientModInitializer {
 // [...]
}