Both lists and document libraries have a Key Filter functionality that can be turned on for that App. Key filters will show up in the left navigation for that App, and provides some advanced filtering capabilities (especially useful for Date or Number fields, as you can do greater or less than filtering).
Activate Metadata Navigation and Filtering
On each site that you want to use either Metadata Navigation or Key Filters, you must first activate the Metadata Navigation and Filtering Site Feature.
A. Go to Site Actions > Site Settings.
B. Click on the Manage Site Features option.
C. Find the Metadata Navigation and Filtering Feature, if it’s not already Activated, then click the Activate button.
Adding Key Filters to Apps
One the Metadata navigation and Filtering feature is active, you can now add a Key Filter to any of the Apps on that site.
1. Go to the App you want to add the Key Filter to, click on the List or Library Tab, then click on either the List or Library Settings option.
2. Click on the Metadata navigation settings
3. In the Configure Key Filters section, Add the field(s) you want to appear as Key Filters. Click the OK button to save the Metadata Navigation settings.
4. The Key Filter options will now appear in the Left Navigation for all that Apps views.
Example: When you select a Key Filter and click Apply, the App view you are on will automatically filter:
Move Key Filters to the top of the left navigation
One problem with having the Key Filters in the left navigation for the App, is that sites with many left navigation links move the Key Filters a long way down the page. Luckily there is a script you can add to the view to Make the Key Filters the first thing displayed in the left navigation.