So I’m making my level selection menu now, but I’ve never seen anything about loading a scene that wasn’t included in the Build Settings.
Can I load an arbitrary scene from a folder?
no by no means! the scene should be available in the list of scenes when you build it. the only other way is to load an empty scene (which you added to build list) and load asset bundles you want into it. in this way you can load different types of content in that scene.
even if you put your scene in resources folder you can not load it or get it by Resources.LoadAll() it won’t return by the method and can not be loaded by Application.LoadLevel.
Yes, you can. Use AssetBundles for it. They may contain scenes.
Just add your scenes to asset bundle files and put them to streaming assets folder. Then you can load your scenes when needed.
Well, you can… by inventing custom scene file format and instantiate objects from this.