What is the collective noun of toolbox?

There isn't a widely recognized collective noun specifically for toolboxes. However, you could use some general collective nouns that would fit, depending on the context:

* Set: This is a general and neutral choice. "A set of toolboxes"

* Collection: This implies a group of diverse toolboxes. "A collection of antique toolboxes"

* Assortment: Similar to collection, but often refers to a wider range of tools. "An assortment of toolboxes for different tasks"

* Array: This suggests a visually impressive or organized grouping. "An array of gleaming toolboxes"

Ultimately, the best collective noun to use depends on the specific context and the impression you want to convey.