“As the superluxury market has gained strength, at the same time, debt-burdened foreign governments in the aftermath of the financial crisis are looking for ways to cut costs or generate cash,” said Jonathan J. Miller, the president of Miller Samuel, an appraisal firm. “So we see the trend toward consulates maybe receding and the conversion of mansions to single-family homes returning.”

The former Scribner residence on 67th Street is among the candidates for reclamation. It was just listed for sale at $22.5 million by James and Anna Hall of Stribling & Associates.

“This change is reflective of what’s happening in the micro-economy of New York,” Ms. Hall said, “where we’re seeing a new breed of affluent, and often younger, buyers who have zero interest in being subjected to the rules and limitations presented by a co-op board. There’s an autonomy that comes with owning a free-standing property. A townhouse or mansion is almost like a piece of art and there are buyers who appreciate that history and want to be part of it.”

Image 46 East 66th, until recently owned by the Republic of Senegal and now under renovation. Credit... Fred R. Conrad/The New York Times

The Scribner property will require a substantial renovation, but boasts customized newer features like a top-floor glass conservatory. The seller inherited the property and has “no interest in being a landlord,” Ms. Hall said. “We envision two possible end users, an investor/developer or a buyer interested in turning it into their own residence, which we feel represents its best and highest use.”

No. 57 East 64th, which according to its co-listing broker, Paula Del Nunzio of Brown Harris Stevens, is the sole Gilbert-designed house on the market in New York at this time, is listed for $44 million. Another of Ms. Del Nunzio’s listings, the 1903 Charles Ogden mansion, currently the School for Practical Philosophy, on a pristine residential block at 12 East 79th Street, is for sale for $51 million.

A circa 1870s townhouse at 52 East 64th Street is on the market for the first time since 1970, listed at $17.75 million by Deanna Kory and Ileana Lopez-Balboa of the Corcoran Group. As a brownstone it was Miss Edward’s School in 1878, but after a serious limestone upgrade by the architect Frederick Sterner in 1916, it became a rental with high-profile tenants like Ethel Barrymore. The lower floors were for many years the site of a well-known veterinary facility, the Park East Animal Hospital.