We know that Super Saiyan, Super Saiyan 2, Super Saiyan 3, Super Saiyan God, Super Saiyan Blue, Super Saiyan Rage, Legendary Super Saiyan, Super Saiyan Berserker, Super Saiyan Evolution, etc. are all Saiyan transformations, they can only be achieved by Saiyans. But what about Ultra Instinct? Could a human, a Namekian, a frost demon, etc. attain it?
The answer to this question can be drawn from a few scenes from Episode 110 of Dragon Ball Super:
Lord Beerus saying what transformation Goku might have gone through:
Lord Champa in shock after hearing what Beerus said:
The Supreme Kai realizing how Goku's movements linked to what he knew:
The Supreme Kai doubting Goku's ability to reach that transformation:
The Gods being pressurized by Goku's transformation:
All this would mean that it's not an exclusive Saiyan trait or transformation, but an extremely powerful and difficult ability that the Gods and other Omega level fighters are known to use.
I am not very keen on the Dragon Ball franchise, but based on the Ultra Instinct wiki, there are three individuals who use the Ultra Instinct - Only 1 of them is a Sayian
According to each individuals wikis, Whis is of the Angel race, Beerus is of the Beeru's Race, and Goku of the Sayian race. Seeing how the ability is a mental state of the individual, it is quite possible that other races are able to obtain this ability as well - although the prerequisites are not entirely clear, even to Goku
It is not completely clear how this form is attained, not even to Goku himself.
However, this ability is also apparently extremely hard to master, even for gods
It is notorious among the Supreme Kais and Gods of Destruction for being exceptionally difficult to master, even for gods. Goku attains this state during the Tournament of Power