Looks like Bubble is not exposing converted to list…I think this is because they fail to recognize the benefit of exposing this for more than just data types or option sets and the generic data types like text or number should also have those exposed.

In that case, put together the custom state list, make it type text. On page load, run a set state action to set the custom state to the value set you have from the database. Then setup a workflow trigger for ‘when inputs value is changed’ and run the action to set the custom state, the value should be the custom states value plus item this inputs value. Then the RG can reference the custom state list.

Are you going to allow users to use the same input to add multiple values, or is it that you want them to just add a single value from the input. So for example, will a user be able to add a value like apple, then clear the input and add another value like orange? Or is it that they can just add apple, and if they cleared the input and then entered orange, that the value of apple should be removed from the list?