Ramp Freq's
Assuming you are using Jeppesen charts, and are talking about New York, La Guardia...
I would say that the only "ground" frequencies are clearance on 135.200, Gnd on 121.700 and Copter Clearance on 121.870.
That being said, you can find ramp frequencies at certain airports e.g. KLAX 10-9B.
As far as La Guardia, I also looked in the AF/D and could find no reference to the ramp freq.
I'll take a look at our tailored charts tomorrow and see what we have printed on our charts for the airlines.