The top 100 list has already been posted, but I thought this article makes some interesting observations on the list.
Overall the variety of games and experiences on that list really show how versatile the deck is, and that people can still have a great time with games that aren’t a perfect experience on the deck.
Yes, it requires it runs well with default settings, everything is accessible with the standard deck controls, that all the control displays use the steam deck icons, and it doesn’t reference controls the deck doesn’t have. It’s a very high bar.
Also UI has to look good at either 720p or 1280x800. A lot of modern games don’t do that well at low res.