Could you please explain a bit for the unique items here? If you mean an item filtered with some special condition, then I think the filter Array Action would work with your scenario.
Personally I think the selection from Array is not available.
The data being queried are not pre-loaded when configure the flow, so there is no data could be chosen from the array,
Further, the data which would be loaded in array might change, the pre-configured item may not work.
what we could do when configure the Flow is working with conditions, or the available OData Query option, such as fiter query, orderby, or select query (in SQLServer).
If I misunderstand something, please let me know.
if an input is an array with items a,a,b,c,c then I'm wondering if an Action in Flow can output just the unique items, so a,b,c.
Use the built-in union or intersection functions. They are both fast and require few steps:
See here for more details: https://medium.com/@martinfy/the-fastest-way-to-find-unique-items-with-flow-f9618ef7224
Learn to digitize and optimize business processes and connect all your applications to share data in real time.
Attend in person or online, there are incredible conferences and events happening all throughout the month of September.