Apple TV 4K- What channels can I get?

There are channels you can subscribe to through the AppleTV app.

Subscribe to Apple TV channels in the Apple TV app - Apple Support

Subscribing through the AppleTV app means you don't have to download an app, you watch through the AppleTV app and all your subscriptions can be managed through your apple devices and Apple pay.

PS.

There aren't hundreds or thousands

Yes, the App Store. If you have any other Apple device, you can browse the available apps there and any that say “Apple TV” will be available for it.

There’s literally thousands and thousands of apps. The list is the app store.

Apple TV’s don’t hav channels in the traditional sense. What it offers is access to a ton of streaming apps which include those mentioned. “More” would be a literally hundreds if not thousand’s of other apps from the App store, impossible to list them all here.

Things like Peackock, Paramount, Fox, Hulu, Sling, AMC+, Showtime, Acorn, Britbox, CBS News, ABC News, NBC News and ton of other things. Most of course requiring a subscription to each service.

Not really what the OP was referring to. None of the mentioned ones in the original post appear as channels inside the Apple TV app.

The Apple TV channels are just a subset of available subscriptions, the list at Macworld is not complete, and is only for the U.S.

My answer addresses the question. They were not referring to channels inside the Apple TV App as evidenced by the fact none of the mentioned providers there have channels inside the TV App.

They mentioned channels as a general term, not referring to the specific subscriptions in the TV App.

Here's an article explaining and listing the channels:

https://www.macworld.com/article/232597/apple-tv-channels-faq-price-channels-list-availability.html

And your answer doesn't address what was asked at all.

He asked about channels, not streaming services.

My answer addresses AppleTV channels directly.