How can I review in a list what accounts (that are not parents) are missing to be linked to a parent

Hi, the business is in charge of the accounts maintenance. We have a strong structure there with 3-4 level of parents. and if a new account is created and not assigned to a parent, then when we run the Balance reports, and they have a balance, the system will show that account at the end of the report (since it has no parent). However, is there a way to know what child accounts do not have at lease one parent assigned?

there are some cases that the business creates the account but it is not used in that month...

Thanks in advance,