Waiting at Peckham Rye recently, I was struck by the extraordinary variety of operators and liveries for a 4 platform station, all at high frequency. 8 Southern per hour (reduced to 4 much of the week at present) and 8 Overground from platforms 1 and 2, and 8 Thameslink (at peak times) and 4 South Eastern from platforms 3 and 4. Obviously there are many large stations with such intensity from different operators, but many of this size?
6 operators' services pass through Haymarket, with all but one stopping. It has 5 platforms (one being a rarely used bay).
Stockport has 6 operators and 6 platforms (one being a rarely used bay).
Stoke has 5 operators and 3 platforms.
There are quite a few 2 platform, 4 operator stations. For example, Brough, Durham and Sunderland.
Morpeth has 5 operators with 2 platforms.
Carstairs has 2 platforms and 3 operators which stop, with a further 3 passing through. Given how isolated and small a place it is, that's pretty impressive.
Dore arguably wins ratio-wise, with its single platform having 3 operators.