The Man with No Name. He has a name.

In “A Fist Full of Dollars”, the Grave Digger calls him Joe, repeatedly.

In “A Few Dollars More”, Lee Van Cleef’s character turns in a bounty, and asks about another one. The Judge who pays the bounty tells him another man asked about it already, and said that man’s name was Manco.

Thus we have The Man with No Name’s name. Joe Manco.

In High Plains Drifter, the Stranger is not the same person. The Stranger has the name Jim Duncan.