Does that mean that a succession was opened and that an Affidavit of Death and Heirship was filed? That is usually what someone means when a list of heirs is mentioned.
Now, that being said, only heirs (called “legatees” if there is a will) that would inherit are usually mentioned. If there are children, spouse, and so on, then cousins, etc., would not be listed anywhere in the succession because they would not stand to inherit anything.
If that is not the case and there are heirs who should be listed because there are no closer relatives, then someone needs to intervene in the succession. Unfortunately, that would require hiring a lawyer to do it properly.