Deciding what to play with a friend often takes longer than the actual gaming session.
To fix this, I just built another tool: Steam Play Together
It's a quick 1v1 comparison tool: paste two Steam profile URLs, and it immediately cross-references both libraries and wishlists.

What it does:
Instant Match: Shows multiplayer games you both already own so you can launch something right away.
Wishlist Overlap: Shows games you both want, or games one owns and the other has wishlisted.
Deals Tracker: Highlights when shared games or wishlist items are currently on sale.
Zero Setup: No sign-ups, no logging in with Steam, no permissions needed.
Once you generate the comparison, just bookmark the URL. Next time you want to play, you can open that link directly without pasting your profiles again. It will automatically fetch your latest games and wishlists.
Give it a try next time you're planning a session and let me know if you run into any bugs or have ideas for features!