How can I tell if a game is supported by Nvidia Gamestream?

How can I tell if a game is supported by Nvidia Gamestream? Is there a comprehensive list published somewhere?

As you mentioned, the Nvidia Shield page lists games allowed by Gamestream. Although there's no way of filtering this, Gamestream games are indicated by an icon to the side.

It's not very elegant, but you can count the number of games by going to your browser console and entering the following:

$(".gfn-game-name").has(".shield-gamestream-support-icon").length

which currently gives me 631 games.

You can also do a rudimentary (and irreversible) filter with something like this:

$(".gfn-game-name:not(:has(.shield-gamestream-support-icon))").hide()

You can also enter this in your address bar by adding javascript: to the front, i.e.

javascript:$(".gfn-game-name:not(:has(.shield-gamestream-support-icon))").hide()