My name is Kenneth Lassesen
. I have most of this information also on Ancestry (often with images of churchbook records). My main focus are the easy trace families that originated with a single person.
Kalthoft | Kaltoft: The first generation of brothers were gunsmiths to the Tsar, Charles II of England, Patented repeating rifles in France, and my own ancestor, Minister of Munitions for Denmark during the Danish-Swedish wars. Other brothers founded iron smelters in Norway and Sweden. If he had lived 50 yrs later, he would have been granted a title for his services (unfortunately, commoners were not allowed this when he died). All people with this name are related
Mollerup | Moldrup | Moltrup: The first generation obtain the name-patent from the crown and was a very successful (and hard-nosed) merchant. Descendents were merchants across Denmark, eventually moving down into owning large farms. All Danes ?North Germans with this name are related.
Lassesen: When family names became standardize, "Lasse" was a version of Lars. For some reason, the informal Lasse was used (according to legend, a priest stuttered and they decided to keep the Lasse -- after all God granted this family name! All Lassesen's in Denmark are direct descendents of Ole Lasse Larsen. He was a successful farmer and parish official.
On my wife side's there is Irish (surviving records are sparse), Norwegian (solid records) and American (a nightmare because of no centralized record keeping prior to 20th century.