ncHoverName is a little addon that shows the name of the mob/player you are hovering over in the WorldFrame. Class coloring and reaction coloring is enabled. The name is aligned 20px above your cursor.
Install & go. No config.
if GetMouseFocus():GetName()~="WorldFrame" then return end
if GetMouseFocus():GetName()~="WorldFrame" or UnitIsPlayer("mouseover") then return end