If you restrict it to just train access to airports, there’s quite a few as well that are not genuinely underground, many are “at grade” or elevated. Ones that come to mind include HKG, LGW, LCY, SFO, JFK/EWR although they’re not really airport rail as such), PHL, BNE, OSL, YVR?, PVG, PEK, DXB...