ItemPicker(single item selection) and MultiItemPicker(multiple item selection) as formula parameter types are available.Only available for: 

• custom action buttons
• administration scripts
• overlays on state transitions

The target list is defined by the scripter in a script (prerun). Example:

[PreRunEntryPoint]
        public void PreRunCode()
        {
            int targetListId = 542;
            var fps = ScriptContext.ScriptParameters.Parameters["FormulaParameters"] as List<FormulaParameter>;
            fps.First(fp => fp.Name == formulaParameterCode).ExtraParameters.Add(API.Objects.ScriptParameters.Type.ItemPickerTargetList.ToString(), targetListId);

        }