The National Association of Unclaimed Property Administrators (NAUPA), a “free national search site to reunite you with your unclaimed property maintained by the state officials who are safeguarding it” links to state, federal, private and Canadian agencies to which personal property and funds have been escheated.

Sites can be searched by name, and will variously provide you with the name of the originating institution, the refund amount, the account holder’s address and the amount owed.

The California State Controller maintains and sells a database of unclaimed property owners, and one listing the decedents and their heirs of estate accounts remitted to the state. Other state Controller Offices and county treasurers also compile this information.

The U.S. Tax Court, the judicial body that hears tax payment disputes, has an online docket inquiry, searchable by indvidual or corporate name or docket number. [Thanks to DetectiveForums.]