That would depend on what basis you are filing for on the I-90. For example, if USCIS has made a mistake on the green card, you may have to prove their mistake. Hypothetically, if USCIS makes a mistake on your birth date, you may have to submit a copy of your birth certificate with an English translation. If USCIS makes a mistake on what category you are under on your card, you may have to prove your visa category. Here, you would submit copies of the approval and the application for your original immigrant visa (family, business, asylum, etc…).
Unless there is something wrong with the card that you have, the answer to this is that you probably do not need to provide anything. Without knowing the reason for filing the I-90, it is impossible to give you concrete advise about what to file. And the truth is that we generally do not file anything with our I-90's because there is simply nothing to file.
If there are any questions or doubts, CIS will generally issue a request for evidence on the pending application and will ask you for what it deems relevant to adjudicating your application. Just make sure you advise CIS of any changes in your contact information so that you can be informed of any need for anything relating to the application.
Barring any big concerns or mistakes with the previous card which you are filing the I-90 to replace, you probably do not need an attorney. I am guessing that your question arises as a result of reading the question asked on the last portion of the e-filed application as to whether you will submit additional documents in support of your application. While the concern is understandable, there is most likely no need to file anything.
If you have any questions or doubts, consult with an attorney who can respond to your concerns.