I don't think this is a complete list, and you should talk to your co-op's attorney to get a complete list, but here is what I think you will need.
1) Minutesfor attorney perusal
2) Ability to provide copies of the Offering Plan & Amendments to purchasers and share holders for a set fee.
3) Annual Financials for the building provided by the building's CPA
4) A copy of the co-op Questionnaire to banks.
5) A copy of the building's insurance certificate.
6) and most importantly a reasonable yet efficient Purchase Application Package and Alteration Agreement with appropriate fees fully disclosed.
I am sure there is more, but I hope that helps for now.
Please contact me for more info if you need it