The All-Lines Railrover is the most expensive Railrover that can be purchased. As its name suggests, the holder can travel on all National Rail services in the UK. Yet no publicity has ever been given to this ticket. The Association of Train Operating Companies (ATOC), who is ultimately tasked with producing the publication, has shyed away from doing so as billing each TOC for their proportion of the cost would, apparently, be rather complex. According to Barry Doe, they've also used the excuse that the All-Lines Railrover is only ever used by enthusiasts "who know it exists".
Proof, however - if ever it was needed, is shown below.
The advert for the All-Lines Railrover forms page 5 (of 8) in Northern's 2010 publicity promoting its own plethora of smaller, more localised Railrovers. The All-Lines Railrover cannot be seen when searching an equivalent online page within Northern's website, which is a shame; instead, the pdf version needs downloading.