Game Development

Async/await and Tasks in Unity. They basically work similar to Coroutines, but without the boilerplate code required.

I'd even say that Tasks and async is better in most of the cases you'd use a coroutine for - the main difference is that Coroutine is tied to framerate, and is guaranteed to be executed every frame (unless you yield something that waits longer), which is something you can't do with Tasks. But most of my Coroutine usage is tied to WaitForSeconds, and that's where Tasks are IMO better suited.

Unreal's Dynamic Delegates are very limited. If you don't need to expose delegates to Blueprint, use normal (non-dynamic) delegates instead. Not only are they faster, they have tons of features that are not available on dynamic delegates.

In unity you can call a lot of internal stuff using reflection.