You can create value parameter and apply them to a custom
node.
To create a value parameter:
Open the custom node graph and select Create node >
Parameters > Value parameter in the contextual
menu.
A new node is created.
Double click on the Value parameter node to open its
parameters.
Name the node.
Add a Description.
Set the values.
Set the Visibility. By default, the parameter
is always visible. When Hidden when or
Disabled when is selected, additional parameters
appear to define the condition in a second combo box that contains
the list of all parameters of the On / off parameter and List
parameter. See Parameter
visibility for details.