Before his mother died in 2018 at the age of 84 , Thomas G. Plante used some of his time on frequent visits to her home in Rhode Island to help get her estate in order.

Early on, he found a life insurance policy that a relative had bought for her in 1933 , when she was born. Because his mother had always lived in Rhode Island, Mr. Plante searched the state’s unclaimed property website for other assets.

“I knew that if there was any money, that’s where it would be,” he said. “Once you start looking, you find — wow! — she had a bank account I didn’t know about.” He also found that she owned a few shares of stock in AT&T , SBC Communications and Brighthouse Life Insurance , and had a number of uncashed dividend checks.

The total value of her financial assets was modest, a little more than $10,000, but Mr. Plante , 59 , said it was enough to give her a proper funeral, which was important to his mother, who was Catholic.