I'd love to see a couple improvements to Dynamic Collections in the Library:

1. Add an option to filter down game demos. Steam already classifies game demos as a separate entries in the system, and it seems like it would be easy to aggregate all of them in your library. With more and more games offering demos, it's now becoming necessary to organize them and queue them up the same way I manage my backlog for purchases. It'd be great to isolate them all.

2. Add a filtering option that lets you aggregate games you've added to your library within X days or X months. Especially during sales, I'd love to see everything I've purchased recently, or simply get an idea of "what's new" in my library without using the "Recents" feature in the sidebar, which includes games I've played recently too. Mixing the two concepts feels weird to me.

I'm sure we've all had the same realization after a Steam sale: "What the hell did I just buy?" after adding 20 cheaper wishlist items to the cart. XD