In the catalogues the smallest size (pattern number 331 40 01) is just listed as a 1/16 litre bottle with no specified purpose, so generally they can be used for anything. With the silver mounts - possibly perfume? I suspect it's more a collection than a set.
Sadly the mounted decanters don't appear in the Holmegaard catalogues, as they are just standard bottles that were bought up and added to by Dragsted.
At one point these small decanters were also supplied to a kitchenware company who packaged them with small wooden (teak or walnut) stands for use as cruet sets - oil and vinegar bottles. Similarly, these also don't appear in the Holmegaard cats.