FlowReactor comes with a generic enum type which can be used for your custom nodes and Blackboard variables.
Example
// Define your enum like this:
public enum MyEnum
{
A,
B,
C
}
// To make sure we can select the enum from the Blackboard we need to add the FRVariableAttribute.
// Create a custom class and inherit from FREnum and set your custom enum as type
[FRVariableAttribute(Name = "MyEnum")]
public class MyCustomEnum : FREnum<myenum>{}</myenum>
// Now we can create our new enum variable field like this.
// Important: You have to create a new instance of your enum by using "new"
public MyCustomEnum testEnum = new MyCustomEnum();