Adding a correction here. There is indeed a standard for Unreal.
X = Forward. All of your props, particle effects, etc. should be X forward as that is what the engine expects.
One exception is that Y = Forward on characters. I have no idea why this is the case, but it seems to have stuck from a long time ago. This doesn’t change the fact that Sockets are still X forward however.
Every Program and Engine has its own standards however, so if you are on a project, you need to learn the standard and ensure your models and effects are oriented correctly, otherwise you’ll never hear the end of it from programmers.