I think you need to use two objects - TextBox and List.
In "TextBox On Text Changed" event you can refresh the list of items for the List. For example, if you keep these strings in an array, you need to clear the list, then loop through the array and check if
lowercase(left(Array.At(loopindex), len(TextBox.text))) = lowercase(TextBox.text)
If this expression is true, add this string to the list.