Extragalactic Magnetic Fields - General Information That I'm Missing I have started studying Extragalactic Magnetic Fields, and mainly focusing on Biermann Battery Theory. I have gathered much information on other Dynamo Theories, as well as about our current Observational and Theoretical status on Magnetic Field Genesis.
What I'm looking for though, is a general "picture" on Extragalactic Magnetic Fields, as a whole. Faraday Rotation, AGN Jets, are basically the topics I have tracked, but I'm pretty sure there are a lot of others.
So I'm asking, if someone has studied in-depth extragalactic structures and magnetic field, possibly could guide me on some of the main and hot topics around them. This way I would have more knowledge on the topic which would be great for me!
I mean just Topic-Titles, would be great!
 A: 
So I'm asking, if someone has studied in-depth extragalactic structures and magnetic field...

The following article on interstellar and intergalactic magnetic fields would likely be a good place to start:
J.L. Han, Ann. Rev. Astron. & Astrophys. 55, pp. 111--157, doi:10.1146/annurev-astro-091916-055221, 2017

possibly could guide me on some of the main and hot topics around them...

One of the neat ways astrophysicists study/observe these fields is by looking at the polarization of dust particles in galaxies, around stars, etc.  The idea being if the dust is ionized (it often is), then the resulting electric dipole moment should align with the background magnetic field.  One can then use Stokes parameters to determine the electromagnetic radiation properties and then invert those to determine the dipole orientation.
The presence of fields also causes Faraday rotation, which can be used to determine/map the fields.  This has recently been used to examine gamma ray burst properties (e.g., arXiv eprint 1705.08531).
