What are the options for a family with an I-829 pending for 18 years?

You could ask to be withdrawn or excluded from your parents' pending I-829 petition. Keep in mind that a conditional resident, which is what you are, is not eligible for adjustment of status. One option might be to travel to your home country, or even a border post, and relinquish your conditional green card status (Form I-407) and then reenter the United States, not as a conditional resident, but under your advance parole travel document based upon your pending adjustment of status (Form I-485). It is very important that you have the advance parole travel document in hand before you leave the United States. Also, you should consult with an experienced immigration attorney prior to taking any of these actions.

An experienced EB-5 immigration attorney will be able to advise you. A U.S. senator or congressman may be able to make inquiries on your behalf in regard to the pending I-829. An option would be to file a Mandamus Action in federal court in which the federal judge would require USCIS to make a decision on your case. The alternative would be to withdraw your I-829 petition and then USCIS would continue with the processing of the I-130 and I-485 application for conditional permanent residency.

I would highly recommend that you schedule a consultation and have your case reviewed by an experienced immigration attorney in the United States. Depending on the facts, it may be a good option for you to seek relief in a federal court.

Are you represented by counsel? You should seek relief in the federal courts. I would have long ago.

You should definitely schedule a consultation with an immigration attorney to fully review your immigration history and options to move forward. These are complicated issues that require full review and analysis by a licensed U.S. immigration attorney.