Free Databases for Genealogical Searching

This site is limited to free databases which cover a lot of ground. It came out of frustration with websites which listed so many minor databases that the "gold" was lost. It is as simple as possible, but some basic knowledge of genealogy is expected. This is it -- I do not intend to expand its scope (but will add similar databases).
Some databases are incomplete, or may be on-going (this is not always made clear by the sites). Small databases or those for smaller areas are generally excluded although there is a bias to British and otherwise English-speaking sources. The assumption is that users will want to search by surname (but see the Occupations listing).