Many of the "interdisciplinary" fields are open to physics graduates. Sometimes it's a matter of just checking out the individual websites. Sometimes it's not a specific degree that's needed for admission as it is, a specifc set of courses... courses that you can pick up as electives in your senior year if you need to.
Some "tangential" graduate fields that a physics BSc graduate may want to look into:
- medical physics
- health physics
- geophysics
(Sometimes the above are part of graduate programs in physics, sometimes they are separate.)
- neuroscience
- materials science
- biomedical engineering
- electrical engineering
- nuclear engineering
- mechanical engineering
- Earth and atmospheric sciences
- applied mathematics or modelling
- complexity science
- computer science
- informatics
- environmental science
- physical chemistry
And then of course, provided you have the prerequisites there are also professional programs such as medicine or law. Physics graduates tend to do rather well on the MCAT.
And as far as applying to each with a physics degree, I think in most cases what matters is that you satisfy the admission requirements by having covered the prerequisite material. If you have it likely won't matter what your degree is. If you haven't, you won't be in the running anyway.