To get list RIC programmatically, there are some chain RICs which you can use to retrieve underlying RICs for some specific indices.
RIC FX= will return a list of World Spots RICs but you have to parse RIC name and the next chain RIC from field list returned by root RIC.
There is a StarterConsumer_Chain example which demonstrates the usage. When you set a chain RIC in the application config, it will return underlying RICs to console output.
As far as I know, we do not have one single chain RIC which can return list of all Forex based products. However, the content support team should be able to provide list of the RICs you want. I suggest you contact the support team to get list of all Forex based product for Thomson Reuters Elektron Real-Time data feed.
You can submit a data query to the content team via Get Support. In the product field, please select Thomson Reuters Elektron Real-Time.