>>290091383
Unity worlds will always have at least the skybox as a cubemap, and most worlds have additional baked reflection probes. Standard shader will use it, and most common custom shaders like UTS2 will show it if your material is shiny enough. Most custom shaders will also allow a custom "matcap" cubemap that you specify yourself though.

For eyes, crank smoothness up to 1.0 and you should see reflections. Note that specular highlights require realtime lights which most worlds don't have for performance reasons, so you still might want the fake specular anime eyes or a matcap for those.