Very little is known about this Mayflower passenger.
William Holbeck came on the Mayflower as a servant, or apprentice, to the William White (1570-1621) family. Since he was termed a servant, and did not sign the Mayflower Compact, he was likely under the age of 18 or 21 at the time.
A search of English baptism records has turned up at least four candidates named William Holbeck who were baptized between 1600 and 1610, including at Fillongley and Shustoke, co. Warwick, and Spofforth, co. Yorks. Since the White family is thought to have come from co. Lincoln, the baptism that is perhaps of most interest is 24 April 1603 at Gainsborogh, co. Lincoln, son of John. Unfortunately without any definite ties to a Mayflower passenger, it will be difficult to prove William Holbeck's true origins in England.
Cole's Hill Memorial
A large monument was erected in 1921 on Cole's Hill in Plymouth, Massachusetts to honor the many pilgrims who came to Plymouth Colony in the Mayflower but died during the first terrible winter and were buried here. This person is one of those person's listed thereon.