What language do the aliens speak? What kinds of sounds do they use? What is their policy/convention when interacting with humans? Use this to think of alien names.

For example, if alienspeak sounds very clicky and jagged, think of names with a lot of coronal consonants (like the /k/ or /t/ sound). If alienspeak is rounder and more continuous, think of names with more vowels and labial consonants (like the /g/ or /m/ sound).

If the aliens and humans don't have a peaceful relationship, they may only have their name in alienspeak. However, if the relations between aliens and humans are smooth, perhaps the aliens will choose friendlier names to the human tongue.