I'd say:
Supernovae
Gamma-Ray Bursts
Hyper-Active Blackholes
Super-Massive Blackholes
loving MAGNETARS BITCH
Pulsars
What do you think? My top one is really the Magnetars. If close enough, they can tear the mere atoms from your body, forget up the electrical nerve system in your body.
The magnetic power of the Megnetars is trillions more powerful than a CME. It is also releases gamma-ray bursts and x-rays. They are the size of Manhattan, and are way denser than the Sun.
Three for the price of one.
Of course none of these are close of us and can affect us unless a gamma-ray burst hits us and is still strong.