One name in my family was a nightmare to research when I did it about 10 years or so ago and still fairly new to it.
(Eliza and Thomas) Mcrea can be spelled in many ways (mcrea, McRae, Macrea etc).
The family moved from Scotland to London, then Southampton.
On the 1841 census it was spelled how I'd imagine someone in southern England would hear it pronounced by a Scot, McCree.
Their son died 1842 and his name wrongly transcribed on the index as McCrab. And when Eliza died, 60 years after her husband, his name was unknown by the person registering her death and had her as the wife of George.
Another line changed there name from Hulme to Holmes, Luke Hulme had a very unhappy and violent marriage. He divorced, met someone else, married again and had another family, although the 3 children are registered as Hulme, they were baptised as Holmes and used that name from then on. My line from him and his first family still use Hulme.
Apart from those, I've found many records mis transcibed