What is a collection or a great number of baskets called?

Not specific to baskets, but generally applicable to any manufactured item (often used in a production context), one option is Batch:

a group of things or people dealt with at the same time or considered similar in type: The cook brought in a fresh batch of homemade cupcakes. We looked at the job applications in two batches. (Cambridge.org)

From the same context, but also generally applicable: Lot:

an amount or set of things, especially when there are several of these amounts: I've already done one lot of washing. Another lot of visitors will be here this afternoon. (Cambridge.org)

Both of them are used to reference a particular "set" of items that were manufactured or processed at the same time or in the same location, to distinguish them from other similar (not to say apparently identical) sets:

Batch number is also referred to as “lot number”. Recording of the batch and batch number typically starts at the manufacturing plant. Batches should be maintained and recorded according to:

• Quantity
• Manufacturing cycle
• Expiry date
• Weight of the active ingredient
• Excipient(s) (lfatabletpresses.com)

Here is an example in the wild (no commercial ties!):

Fresh batch of baskets have arrived in a variety of colors and sizes? Open today 11-7 (facebook.com)