I do know a few evil internet forum posts that explain and go through quite a lot, but a comprehensive list of providers would be hard to find. Lots of paid ones pop up on searches, as ads, paid content or on shill review sites, so it's difficult to find quality information regarding all of them. There seem to be ones that have thousands of channels that mostly use world tv stations, and niche specific ones though (movies, cartoons, reality tv, etc.). Some paid providers use proprietary software for watching, while others provide .m3u lists of channels that you can open on VLC Player. Some .m3u files only work if you pay for a service and provide credentials or have a specific ip, and some are free. They're usually called "IPTV lists".

Here's a number of free lists grouped by country, language, region, category, etc. It's where I got the one I linked in my previous comment from.

Here's a good conversation about services that was later deleted, but you can read most of the comments from that webpage.

Regarding how to configure smartTVs and other devices to watch is a whole other thing. What devices would you like to use it on?