I've tried to use the search but it doesn't quite work very well on my mobile device.
Edit- Thanks a lot everyone I have lots to look up. Feel free to keep posting because everything helps and I'm sure there are others with the same questions who will see this too
If you want to stream local media or media on your network I would use SPMC, Kodi, or Plex. All 3 of those should support surround sound and have nice user interfaces.
For streaming media Netflix and Amazon are pre-installed and you can get apps from several cable networks like HBO, Showtime, FX, and some others.
Anything that is not supported as an app might also work as a cast app from your phone.
It's hard for anyone tell you which apps to download since we don't know what you are looking for.
SPMC (Kodi for Android) or Kodi then install the Exodus add-on.
My most used apps are the following:
If I wanted live tv I would probably try either SlingTV or maybe the upcoming Youtube TV. That said, I only tried SlingTV once a year ago.
Sorry, not much in the way of free options there.
Here's a list in no particular order: PuppetMaster TV with rekodi repo, SPMC, Live Channels, Crackle, CONtv, CipherTV2, Haystack TV, Pluto TV, Tablo (requires external tuner/dvr hardware), FandangoNow, Vudu, Podbean (if you like podcasts), Amazon Music, and iHeartRadio
Add Tubi TV to your list. It has commercials, but lots of free content.
Open the Play Store app on the Shield and start downloading anything that looks interesting.