Websites with free access to transcripts and databases of essential genealogical records

FreeUKGenealogy is a charitable organisation providing free online access to family history records through the work of volunteers who aim to create high-quality transcriptions of public records from governmental sources, parish churches, and other trusted institutions. Their work includes:
FreeReg – a growing database of baptism, marriage and burial entries in church registers (some from 1538) and other relevant sources.
FreeBMD – a growing database of birth, marriage and death records.
FreeCen – a database of the 19th century UK census returns.

FamilySearch – a nonprofit organization and website offering genealogical records (mostly transcripts), education, and software. It is operated by The Church of Jesus Christ of Latter-day Saints (Mormons).
GRO: General Register Office – search (free of charge) the historical birth and death indexes for England and Wales. This is also the place where you order copies of all birth, adoption, marriage, civil partnership and death registrations direct from the government’s own official website. Searching the indexes is free but any items ordered must be purchased.
Find a Will – freely searchable database of probate granted since 1858. Also soldier’s wills. If you wish to order a (digital) copy of the documents there is a charge (currently £1.50 per will).
UKBMD – links to websites that offer on-line transcriptions of raw genealogical data, including both the original registrars’ indexes and the GRO’s secondary indexes of UK births, marriages, deaths.  Censuses, parish records, wills, monumental inscriptions etc. are also included.
UKGDL – links to websites that have on-line data to help you discover what your families did and how they lived, including school lists, trade directories, electoral rolls, passenger lists, etc
UKMFH – links to websites that offer online information in a wide range of categories to help with Military Family History research.
Historical Directories of England and Wales: University of Leicester – a free-access collection of 689 directories, with at least one for every English and Welsh county for the 1850s, 1890s and 1910s, including Kelly’s and Pigot’s, as well as regional publishers. Searchable by name, place and occupation.  The collection is also available, with additional search options, as part of the Ancestry collection.