Any collection in a Headless CMS (H-CMS) base can be filtered and sorted exactly the same way as you can sort or filter an Excel data source.
NOTE: Filtering is different from the use of Headless CMS variants. With filtering, a unique set of collection items is determined. With variants, the list of items remains unchanged, it's the value of certain item properties that change.
How It Works
Each base used in an experience has a set of associated actions for filtering and sorting collection data.
When accessed through the Triggers and Actions panel, the "ACTION category" column will identify each collection separately.
In the image below, the "base contains the collection: "Days". (The "Sync" category is universal to all bases.)
Filtering and sorting are applied to the local copy of an H-CMS base that is present on every Player device running an experience using that base. As a result, filtering and sorting do not require an Internet connection and can work while offline.
Of course, while offline, your local base copy cannot synchronize with the cloud-hosted master, so if you're making frequent changes to base content, the occasional network connection on a Player device will be necessary.