I G I for the whole country (1992 version)
The International Genealogical index (IGI) is a remarkable index, compiled by the The Church of Jesus Christ of Latter-Day Saints. This index contains many millions of baptisms and marriages but NO burials. The most recent date is about 1885 but the majority are much earlier. Not all parish or non-conformist registers are included and coverage vary from county to county. (See Philemores Atlas)
Boyd's Marriage index
This is an index of English marriages, taken from copies of marriage registers, bishop's transcripts and marriage licences, covering the period 1538 to 1837. Not all counties are included in this index and few (if any) are complete.
Lancashire (101 parishes)
Northumberland (84 parishes)
Somerset (120 parishes)
Yorkshire (206 parishes)