FX and Nat Geo are shown at FIOS channel list link shown below. Yes we have customer designed wiki website for channel listing since Verizon makes it SO difficult to have an updated list of channels. The Verizon website has a very messy graphical interface that is very cumbersome to find channels and never updated with the newly added channels.
Below are the two channels that Verizon is lacking authorization:
553 FX HD
621 Nat Geo
Note: It not all bad as most Roku channels authenticate with Verizon like WatchESPN/ESPN/2/3/U, Disney/XD/Jr, History, Lifetime, A&E and probably others that I have not authenticated.
http://www.tvchannellists.com/List_of_V ... S_Channels