Formal:
* A wardrobe of clothes
* A collection of garments
* An array of clothing
Informal:
* A pile of clothes
* A heap of laundry
* A rack of clothes
* A haul of new clothes
You could also use a collective noun based on the type of clothes, such as:
* A suite of suits
* A set of pajamas
* A collection of dresses
Ultimately, the best choice depends on the specific context and the intended meaning.