Well... There's no legality for you, so one approach is just list your email address somewhere like Flippa.

There is legality for anyone mass mailing to the list they buy + that has nothing to do with you.

If I were buying a list, I'd only consider purchasing the domain + list, as this is the only way to have any deliverability of email sent to your list + also be in compliance with various legalities of sending to this list.