I did some experimenting tonight with my LG Smart TV and this is the list of servers I found that could be blacklisted:
These block ads in the LG App Store
This blocks the ads that show up here: https://i.imgur.com/2TKYBf5.png
It has some trade-offs, though.
You have to allow it in order to sign any EULA agreements and to download apps. Doing so makes the ads appear, but turning the TV off (standby) and on again with the site re blacklisted clears them.
The App icons and screenshots IN THE APP STORE would not appear.
This was not a huge loss because LG’s app store is tiny. Every other smart TV feature works.