There is a third party site that shows the top charts: http://www.slidetoplay.com/apple-tv-apps-top-list/
But it doesn't have screenshots, description, ratings, version history etc. so not all that useful for buying decisions. Only the App Store on the device currently has that.
It is fairly mind boggling to me as a developer that they don't at least have a way to browse apps on the web using iTunes. But what can you do.
I have emailed the people behind the WatchAware site (complete list of every Apple Watch app in every country) to ask if they have considered. Doing the same for ATV.
No response as yet, but will keep you posted.
I wouldn't be surprised if Apple eventually added an Apple TV section to the iTunes store browsable on any iOS device or computer with iTunes and be able to purchase apps on there for automatic download to the Apple TV. It's something they really need to do.
There's also this site that is curated, vs. listing every single new app (but does have descriptions): http://atvapps.net