Human explorers have found life on other planets: mostly viruses, single-celled organisms, and flora. Nowhere in the Galaxy has life evolved so far as to give rise to more than animal intelligence, however. Humanity is the only technological species in the Imperium.
That is not to say that humanity is the only intelligence in the Galaxy. Humans have invented artificial intelligence (AI). AI is found in limited ways across a number of technological systems, from ships’ computers to medical equipment.
The most advanced forms of artificial intelligences are androids: artificial humans with advanced computing capabilities, and—in rare cases—emotional sub-routines. Emotional circuitry is TL 15, which means that it is highly advanced and somewhat experimental. It is also widely controversial, to the point that in many star-systems emotion circuits in androids are even illegal.