Abandoned/Unclaimed Property — Searching for Unclaimed Property
https://www.mass.gov/searching-for-unclaimed-property

Adoption Records
Access to adoption records
https://www.mass.gov/service-details/access-to-adoption-records
Get access to historic adoption records
https://www.mass.gov/how-to/get-access-to-historic-adoption-records

Affidavits – See county court records
https://www.masscourts.org/eservices/home.page.2