What documents to ask for production in copyright infringement case?

It depends on whether you represent the Plaintiff or the Defendant. And, the nature of the infringement allegations would give you insight regarding which documents to request. If you represent the Defendant, you should look to the elements of infringement ownership of a valid copyright and copying of protected elements of the work. So, the first document to request is the registration certificate, any assignments of the copyright, and copies of any contracts with the author that may give the Plaintiff standing to bring the lawsuit. If the work were registered after the alleged infringement, the Plaintiff loses valuable remedies statutory damages and award of attorney's fees. And, a prerequisite to filing an infringement claim is registration of the work. Next, I'd probably ask for documents related to damages. I would want to see if the alleged infringement caused the Plaintiff to lose sales. If I represented Plaintiff, I'd certainly want to see the Defendant's financial records to determine whether disgorging profits or statutory damages were a better remedy. Of course, every case will have unique facts. Thoroughly reading and understanding the complaint will help you determine which documents to request. Also, answers to interrogatories will help you discover documents that may not be apparent at the early stages. Hope this helps.

You'll need documentation of when the material was composed. Who had access to it privately or publicly? If and when it was played or performed publicly, where, and by whom; and the locations and habits of the alleged infringer (to prove infringement could have happened).

To be able to file any copyright infringement case, the person filing the case must have registered copyright with the U.S. Copyright Office on the work claimed to be infringed. That will show what is registered and the presumed date of creation. Then, you will want any recordings, writings, registration with any PRO or publisher, or anything else that tends to show what was created, by whom, and when. It is your homework. Think about it and you can come up with a good list.