Records of those in the armed forces were kept from 1660 onwards, though not always to the quality or accuracy those researchers of today might have hoped for. Standards incidentally improved shortly into the nineteenth century.
Those seeking out details about soldier ancestors might find official discharge papers more than a little useful, where ranks below officer are concerned.
Close to home, one might find military museums and military societies keep extensive records on their colleagues of years gone by.
For those ancestors engaged in other employment and professional sectors, several guilds and museums have emerged over the years, both to protect the interests of living members as well to preserve the memory and traditions of those who are not. Most of the early guilds and professional associations now have their photographs and other documents preserved in special museums dedicated to the trade itself.
Among other useful sources of data are town directories and town books, more prevalent perhaps in the middle of last century than is the case today. Primary among these directories were such as 'Kelly's', in which each parish and its inhabitants were listed according to name, occupation, address and much other personal and employment detail.
The Percival Boyd Index held at the Society of Genealogists, lists seven million names and-appropriate English marriages and London burials between the periods 1538 to 1837.
Various other departments about immigration and emigration, poor law, and so on, can also increase the store of information you gain on any particular family or specific individual.
Finally, a wealth of information is available in the various genealogy libraries running throughout the world, many of which keep their own records alongside copies of official documentation.