From the Holy Quraan we understand that Allah SWT made the Angels, the Jin and the Human beings and it also tells us that He made us as Ashraf-Ul-Makhlooqat (the most superior beings among all of his creation). To me this alone proves that even if Allah SWT created other types of living beings which are not mentioned in the Quraan, we the Humans are still superior to the rest of them. So using this I assume that there may be more living beings in the whole universe but none more intelligent than us to be able to advance in such technology to be able to contact us or visit us on our planet earth.
This is my understanding from the various verses of the Quraan so what do you think?