There are two major players in smart TV boxes. Apple TV and Android TV. Android TV is the most popular and affordable option. Because Android TV operating system is not limited to one manufacture like Apple TV. You will see Android TV boxes from Nvidia, SkyStream, Amazon, Mi or Xiaomi, H96, etc. It is not a close system. You can install Android apps from any source. Even you can create an Android app and install on your TV box. It
You will find unlimited number of movies, TV shows and streaming apps from Google play store and third-party sources. People tends to install free Movies, TV shows, Live TV apps from other sources. Because those apps are not legal to distribute on Google Play Store and it is against play store policies.
Android TV app Stores
There are many TV app stores like AppLinked, UnLinked, FileSynced, ApkTime and Aptoide TV. Those app stores have different features. App stores like AppLinked, FileSynced and Unlinked are maintained by users all around the world. Any user can create store on those apps and add list of favorites. You may need code to access those stores. For example, get AppLinked code to access AppLinked store that has apps. Many store creators made their store code public in order to facilitate app downloads.
If you want to install Movies, TV shows or any streaming application without any subscription or payment, AppLinked or FileSynced is the best choice. If you use FileSynced, you can find trending FileSynced codes to access those stores. Even you can create your own app store. People use to backup all apps and games. So, they can easily restore their TV box. Because many apps installed on TV boxes are from different sources. It is hard to download and install those apps one by one. You can even share your collection of apps with others.
Aptoide TV is like Play Store TV. No need codes to access. But does not has many free movies and TV shows apps like on FileSynced. If you want to install any Android phone application or TV application that is not available for your region, Aptoide TV is the best choice. No need to download apk files from internet and transfer it to TV box. Use this app store.
APKTime is too like FileSynced and AppLinked. Instead of maintain many users all around the world, APKTime was maintained by one user. No need to use any codes to access apps and games. You will find many free Movies, TV shows apps on APKTime.