There are several people whose origins are mysterious, and are active areas of research.
The first of these is of course Andreas Bentz, who emigrated from Germany to Pennsylvania. We don't know where he came from in Germany, nor what his family ties there might have been. I'm having a DNA test done which should allow some conclusions to be drawn through comparison to Bentzes in Germany and other countries. My hope is that once a location in Germany is known, perusal of records there will establish additional solid family links. We also do not know what happened to him - his descendants settled in the Dillsburg area, but we know of no grave for him. He might have been buried there at the "old Bentz homestead", or at his church in Hanover (the graveyard of which was partly obliterated). Of course his grave might be elsewhere, and we just haven't found it yet.
Eve Marie Swope has been something of a mystery for some time, with some sources listing her as Maria Eva Swope. She was born November 14, 1750, and died January 15, 1839; her tombstone is in Barrens cemetery, at row 8, stone 17. I have concluded after a fair amount of work that she is the daughter of Johannes Georg Swope and Anna Barbara Leyer, in part because of a land arrangement that the father had with Eve's husband, Conrad Gentzler, and the debt Conrad had with a Nicholas Swoope, quite likely Eve's brother.
John D. Cooper disagrees, having this to say:
I have been around the bush several times on the connection to Johann Georg Swope. I think that Eva Marie is definitely a descendent of Johann Georg, but I don't think she is a child. Eva was born 14 November 1750 and married Conrad Gentzler before 1767 when Michael Gentzler was born. The land transaction between Johann Georg and Conrad would be keeping the land in the family to a grandchild rather than to a child. Col Michael Swope, b. 1726, married Anna Maria Spengler and recorded children Christened Jan 1749 and born 1752. The gap between the two known daughters is large enough to accommodate Eva Marie. Based on naming patterns I suspect Eva Marie to be an unrecorded daughterof Michael as opposed to Johann Georg.
I've found a number of references to a Nicholas Swope, b. 14 Dec.1752, in either York or in Bucks County, who married Anna Marie Hager. His father was (Hans) George Swope, b. Oct. 5, 1705. Nicholas may be buried in Clermont Co., Ohio. I think that Nicholas was Eve's brother, hence the reference in Conrad's will. I have no idea who Jacob Remer was, but if he turns up in Nicholas Swope's genealogy (fairly well developed by various Swopes) that might be another bolt holding this identification together.
Julia. An ancestor of mine, perhaps of no direct interest to most other Bentzes, is to locate Julia Cassidy, who lived in New York City from something like 1867 to 1901. I have a web page about her here.