I have two unusual names in my family tree, William Bass Briggs, who was my great grandfather, his grandfather was also William Bass Briggs. I'm not sure where the Bass comes from and am thinking it may an ancestor's maiden name, but not found it yet.
The other unusual name is Mary Trigidiard, who was my great, great, great great grandmother and lived in Cornwall. The name appears to have died out with her as I've not found anyone else with it (Trigidiard) and it no longer exists.
One of colleagues is descended from some Lidyards and think one theory is they arrived in England around the Armada and quickly anglicised their names to fit in. Tre is Cornish and could therefore have been attached to a family called Gidiards.
No proof of any of it, though, so just intereting theories.