Not included here are re-sited stations, or stations on abandoned routes (such as the Metropolitan line extension beyond Amersham and the District line extensions from Acton Town to Hounslow West, and Ealing Broadway to Windsor).
(This information gleaned from Douglas Rose's "The London Underground - A Diagrammatic History", a superb historical map but now sadly out of print. This is a vital research tool - especially for information on abandoned routes, station re-sites and name-changes.)
My circa-1970 Tube map shows the now-closed Strand Station on the Northern Line, between Leicester Square and Charing Cross, which can, in fact, be seen from Northern Line Trains as they pass through, just as can The Gazeteer - a ghost located under/near Monument/Bank, still dimly visible from Northern Line trains if sufficient sparks are generated in passing, which never, as far as I know, resulted in a passenger entrance or appeared on any Tube Map. The Gazeteer's deserted platform is used as a storage facility for pallets of the slightly concave (top to bottom) white tiles once used to line stations. Nowadays, they just don't bother, and use conventional flat tiles for station linings.
I am happy to report that Douglas Rose's "The London Underground - A Diagrammatic History" is back in print in a seventh edition, priced very reasonably at £7.95, ISBN 1-8541-42194 (amazon.com, search).
Incidentally, perusal of the 1933 tube map versus the 1938 tube map shows a station Post Office between Chancery Lane and Bank on the Central London Line in 1933. This appears to have been renamed St Paul's by the next map. It retains this name today. Under Original Name Rules this is a useful technicality. Also, the version of the 1933 Beck map on the LU museum website shows British Museum in place as an interchange station (with Holborn?) despite assertions elsewhere that it never appeared on any modern tube maps. In interchange only rules this is another useful technicality.
(It is true that both of these stations are also shown on pre-Beck maps but most players tend only to use Beck-design boards. For those interested in such things there is an [excellent webpage] with a collection of maps from 1908 (interesting but unusable) to 1999 (twice), including a 1933 map, though without British Musem, a gorgeous 1921 map and the 1970-era map referred to above showing Strand and also Trafalgar Square, both of which were later amalgamated into Charing Cross. There is also another, [slightly more bizarre webpage] that has plans of several stations from various times, most taken from times when the stations in question were being remodelled. My favourite is the photo of a model of the King's Cross deep tubes.)