Twise - in the above panel from The New Laird of Castle McDuck (1992) and in the unpublished sketches of the history of the Clan McDuck, Don Rosa reveals new McDucks. When asked, Don Rosa responded that most of the McDucks in the above drawing are yet unnamed. When it comes to the unpublished sketches the situation is the opposite. New McDucks are mentioned, but are not fully drawn. Interested readers might thus find that one or more unnamed McDucks in the above panel fit the descriptions of previous unknown McDucks in the sketches - what a puzzle…

Previously unknown McDucks mentioned in the
unpublished sketches of the history of the Clan McDuck
Besides a few unnamed McDucks from the dark ages, Don Rosa names 5 previously unknown McDucks in the unpublished sketches of the history of the Clan McDuck. They are:

Sir Sly McDuck (MacDuich), mentioned in 1018 as a spy for king Malcolm II. Sir Murdoch McDuck (MacDuich), mentioned in 1066 as a trader of longbows. Sir Donald McDuck ("Black Donald"), mentioned in 1440 as the inventor of Scottish sports like, golf, throwing the hammer and tossing the caber. Laird Locksley Duck, joined around 1707 the famous Scot renegade Rob Roy's harassing of evil landlords. "Potcrack" McDuck, invented steam-powered bagpipes in 1767.