A map of pols' dreams of the Hong Kong MTR & Shenzhen Metro by 2030. This was tougher than I thought it would be; much of the information I've found online is contradictory.
Not shown: cross-border services between HKG and SZX (I think that was cancelled), the Huizhou Metro (no info in English), and SZ Metro lines 17-20 (too early in the planning stages).
Overview of the entire map.
Detail of the MTR Light Rail
Detail of HK Island, showing the North Island Line and both phases of the South Island Line.
Detail of central Shenzhen and the HK/SZ border.
Big version, as always, right here.