Non-block signals, probably relatively few and far between nowadays, are usually - in my experience - found, mid-section, protecting a level crossing worked by a crossing keeper; that being its sole purpose, the signal is worked (directly) by the crossing keeper. Does that fit what you had in mind?
There are a couple of examples of signals, plated as autos, in the middle of AB sections out in the Lincolnshire Fens, whose only purpose is to allow the sequence at the adjacent AHB crossing to be suppressed whilst a train calls at the station immediately in rear - again, these have no function as far as the separation of trains are concerned, although the mode of operation of the crossing (stopping/non-stopping) will be selected by the signalman in this case. Not sure whether these are referred to as non-block signals too.