1821 Census - Fire destroyed a lot of archived census material in 1922, so info is limited. 1831-1851 is also available on Family Search with further reduced info.
1901 & 1911 Irish Censuses - Searchable facility
Belfast Cemetery - Burial records from 1869. City Council. Searchable facility.
Births and Baptisms - 1620-1881 [Family Search].
Cemetery Records - Search by county.
Cemetery Records - Alpha lists.
Civil Registration Indexes - Family Search.
Convicts - 1788-1849 transported to New South Wales.
Cork - 1845, Directory. Alpha list. In .pdf format.
Dublin - 1850, Directory. Alpha list.
GENUKI - Ireland, recommended reading, very informative.
Griffiths Valuation -1847-1864. Based property valuations, excellent source of info [lack of censuses]. Searchable database.
Irish Genealogy - Various searchable indexes.
Marriages - 1619-1898, Family Search, searchable facility.
National Library of Ireland - Well worth a look.
Petty Sessions Court Registers - 1828-1912 [Family Search]
Prison Records - 1790-1924 [Family Search].
PRONI - Public records of Northern Ireland. Various databases.
RootsIreland - Searchable database.
Tithe Applotment - 1814-1855. RoI [Family search]. Searchable.
Tithe Applotment - 1823-1837. National Archives of Ireland. Searchable database.
Wexford - County Archive. Would recommend reading the 'About the Archive' first. Material looks to be in original format, would need to know an approximate date. Info can be found on the right side of the 'Home Page' under pages, some burial records and other material.
Wills - 1858-1929 [Family Search]
Wills and Administration - 1858-1922 [National Archives of Ireland] searchable.
Ayrshire Roots - Not checked yet, but I understand it is a free to use database.
Dundee - FDCA. 1801 census. A nice find, well worth a look at the full site for other local snippets.
Edinburgh University - Historical Alumni, searchable records.
Find A Grave - Searchable database.
Gazette, The - Search the archives.
Gravestones - Photographic resource.
Immigrant Ships - Depearting from Scottish ports. Includes ships and some passenger lists.
Perth Burgh - Burial registers, searchable database, 1794-1855
Poorhouses - Summarised lists which includes the 1881 census in most cases.
Post-Office Directories - Online books or download as a .pdf
Scotland Births - [Family Search] Maybe either/or Births/Baptisms, 1564 - 1950
Scotland Marriages - [Family Search] 1561-1910
Scotlands Family - Genealogy resource, well worth a look.
Scotlands People - Essentially a PAY SITE, but you can search the indexes for free and it will say if there are matches. There are a few free facilities.
Scottish Indexes - (Graham Maxwell Ancestry) 1841 - 1861 censuses and a number of other searchable indexes.
SCTBDM - Scotland BDM site, read the page this is linked to before going to 'Site Search'
Shetland Family History - Searchable facility and more.
Tiree - Old parish registers.
Wigtownshire - Old Parish Records. Currently not working [one of the old Roots Web links]
Wills - 1513-1925, 'soldiers wills' also on foot of same page.
Births/Baptisms - [Family Search] Wales, 1541-1907. Read the description first.
Caerleon - Newport, South Wales. Nice, concise site with searchable/listed Parish Records. Well worth a look at the full site.
Conway - Parish Register, Diocese of Bognor, 1541-1793. Downloadable or just search the book.
Crime - Crime & Punishment. Searchable database 1730-1830
Glamorgan - Parish registers 1558-1900
General Register Office - [GRO]. Search birth and death indexes [1837-1916] for mother's maiden name [bitrths] and ages [deaths]. You will need to subscribe [free].
Llangar - Parish Records, 1640-1831.
Llansannan - Parish Register, 1667-1812. Downloadable or just search the book.
Marriages - [Family Search] Wales, 1541-1900. Read the descriptin first.
Monmouthshire- Various transcribed Parish Records, well worth a visit if your relatives are there.
Newport - South Wales. St Mary's Church. Searchable Baps, Marriages and Burials, various dates to 1915.
Newspapers Online - Searchable database, 1804-1919. National Library of Wales.
Swansea Mariners - Mariners from Swansea and those who sailed from Swansea. Large searchable database, includes name, year and PoB and ship.
Welsh Wills - Proved in the ecclesiastical courts before 1858, searchable database. In Welsh.