[AnimalMuppet]

It depends on whether you regard quantum gravity as SM/beyond SM or not.

Even if you don't, though, there's still cosmology and black hole physics.

[codethief]

…and (if I may add) foundations of quantum mechanics (which may or may not be related to quantum gravity). And dozens of open questions in relativity alone (that have little to do with black holes).

[hpcjoe]

I personally find the entropy connection with information theory and black holes fascinating.

[jjdredd]

True. I don't know much about cosmology.