Henry Daniel's early connection with Spode means that Daniel researchers will find these links invaluable:
The Spode Society
The Spode Museum Trust
The Spode Exhibition Online
Daniel Earthenware is still relatively uncharted territory but these sites both offer their members valuable databases which include material relevant to Daniel research: The Transferware Collectors Club
Friends of Blue
Much work remains to be done on the connection between Richard Daniel and Masons.  These links provide a useful starting point: Mason's Collectors Club
Raven Mason Collection Exhibition at Keele University
Essential for documentary research in Stoke on Trent, the City Archives are located in the City Central Library, Bethesda Street, conveniently close to the Potteries Museum.  The museum service is also responsible for the Gladstone Museum, which offers a 'living history' experience.  Stoke on Trent City Archives

Stoke Museums
The Potteries Website is a local history site which gives a wealth of background on the area and the manufacturers. The Potteries
The NCS and ECC publications contain articles covering a wide overview of ceramic studies. Northern Ceramic Society
English Ceramic Circle

When trying to identify possible Daniel items, a knowledge of contemporary manufacturers can offer valuable insights and these websites will provide an introduction.
Worcester Porcelain Museum
Coalport China Museum (National Collections of Coalport & Caughley)
The Caughley Society
The Derby Porcelain International Society
Davenport on The Potteries website
Victoria & Albert Museum
The Cumming Ceramic Study Collection (Minton)