There is a PLAYz Media app that is a PLEX client in the LG store for my TV, (The LG- 55UB8500 55" 4K TV) I would figure it is not specific to my TV but the overall store. I didn't try it yet, has anyone been playing with it?
It would really be nice to have HBO Go.
For those asking for Plex there is a PLAYz Media PLEX client in the store. Don't know how good it is because I'm too cheap at the moment to download, It's all of 5 bucks