What is a collective noun for rare?

There isn't a specific collective noun for "rare" in the sense of something being uncommon or scarce.

Here's why:

* Collective nouns describe groups of things. For example, a "flock" of birds, a "herd" of elephants, a "pack" of wolves.

* "Rare" describes a quality or characteristic. It doesn't inherently refer to a group.

Instead of a collective noun, you could use phrases like:

* A collection of rarities

* A trove of rare items

* A cache of rare artifacts

* A selection of scarce objects

The best choice will depend on the specific context and the type of rare things you're discussing.