According to researcher George Fuld, who published a lengthy exploration into Newcomer's holdings between 2006 and 2008, the U.S. section of the collection was nearly complete, lacking only a single double eagle and the 1822 half eagle, of which only three are known. Fuld stated that Newcomer had a complete series of U.S. copper and silver coins. Helping Newcomer in assembling the collection was numismatist George Williams, who spent more than 20 years assisting in the effort.

Taking Fuld's research as accurate, that would put Newcomer's collection at or near the apex of all collections assembled in his time.

Seconding this opinion is PCGS, who in 2004 touched on Newcomer's achievement when it compiled a list of the 10 Most Famous U.S. Ultra Rarities for its Set Registry. In the PCGS list were many of the great story coins of American numismatics: the 1913 nickel; the 1894-S dime; the 1876-CC 20¢ piece; the 1838-O half dollar; the 1804 dollar; the 1870-S dollar; the 1885 Trade dollar; the $4 Stella; the 1907 Ultra High Relief Saint-Gaudens $20; and the 1927-D Saint.

Calling the Newcomer Collection the greatest collection never to appear at auction, it touted the fact that Newcomer's collection contained six of the 10. Missing was the $4 Stella and the two $20 Saints.

To read the complete article, see:
(https://coinweek.com/us-coins/where-does-waldo-newcomer-fit-among-the-all-time-great-collections-of-us-coins/)