Televisions which feature a level of capability without depending on another device. In other words, TVs that can stream, use “apps”, and so on, as an integrated function. Their OSes are usually Linux or Android based, while CPU architectures are either ARM or MIPS.

you can connect the flash to a SD card reader, and rewrite it's contents

By flashing the eMMC in these televisions, rooting the existing Android install is possible. From there, one can add certain APKs, log into the system using ADB, and more.

https://www.exploitee.rs/index.php/Hisense_Android_TV

Not much to say about this one, but it was pulled out of the thing, hacked around a bit to connect up to a Fridge display, and thus, a media player on Linux was created. Maybe this could be rigged into the fridge to make a “Kitchen Workstation” of sorts?

https://www.reddit.com/r/hacking/comments/fnt31u/lg_tv_board_from_work_samsung_familyhub_fridge/

aimed at enhancing firmware and functionality, specifically for Samsung TV models

Less so of an operating system, but directly relevant to installing Operating Systems on various Samsung TVs. Allows access to root, telnet, and more, depending on the TV model and age.

http://wiki.samygo.tv/index.php?title=Main_Page

http://wiki.samygo.tv/index.php?title=SamyGO_for_DUMMIES

the lack of hardware graphic acceleration makes many applications too slow

This may not work on all TVs, but it is known to work on the 46ES8000. Others in this series may also work. Refer to the SamyGO wiki and information for more, as this hack is immediately dependent off of SamyGO.

http://forum.samygo.tv/viewtopic.php?t=7898

http://www.mediafire.com/file/mrt1xecd3db2hqp/Ubuntu_Smart.pdf/file

Since the field is only accessible when the TV is offline, we will need to utilize a USB-UART

While only tested on the VF553XVT, a certain exploit in the Wi-Fi password field allows executing root commands. However, it’s practicality for EOPs is unknown.

https://www.exploitee.rs/index.php/Vizio_Smart_TV_(VF553XVT)