I know you can see psychic matrices if you have See Supernatural. Can anyone tell me who can see matrices (and other supernatural abilities) without that advantage? For example, what about creatures that are Beings Between Worlds or other psychics (the gift specifically says the make can see magic by Free Access to Any Discipline does not say the same for psychics).

No one. Only the beings that have the advantage See the Supernatural can see psychic matrices. Even beings with the capacity to wield psychic powers can't see their matrices.