I don't think the following is still the case, but it's a while since I passed through the stations concerned....
In the 1970s, at some busy Underground stations in the West End, as you descended to the bottom of the first escalator there was a sign saying "Follow the Lights", together with a series of small illuminated panels with names of BR main-line terminals in different colours.
The idea was that different coloured lights were repeated at crucial points in the maze of underground passageways and you followed the appropriate colour through to the correct platform for the Tube heading towards your station. I'm not sure whether or not the colours corresponded to the required lines on the Tube map.
IIRC, the "Follow the Lights" system was only at Tourist Central stations like Piccadilly Circus or Oxford Circus.
And I think only the long-distance London Terminals were covered - Paddington, Euston, Kings Cross etc.
Obviously the system was meant for occasional visitors from distant provinces, not for Home Counties types, who would be expected to know their way around the Metropolis (I don't recall any coloured lights showing the way to Victoria or London Bridge, for example)
Something else I've not noticed on LU recently is sets of red metal Fire buckets full of sand, strategically placed on deep-level platforms. Sand from these seemed to be regularly used to cover pools of vomit on the platform at appropriate times of the week. Today's powder or foam fire extinguishers are probably not as versatile for this purpose.