I have a player at my Starfinder table who is really keen to use her bonuses for identifying rare creatures, but has never gotten a chance to.
I'd assumed none of the encountered creatures were ever rare before because I'd never seen one so-marked in its description or stat block. However, after looking deeper into it, I can't find any instance of a creature's rarity ever being remarked upon at all.
The game however does have a nice table for the DC of Identify Creatures checks, based on rarity, but I don't see what use that is if there's no way for me as the DM to determine if a creature is common or rare. The only guidance on this I can find anywhere in official materials is on the DC table, where it says Space Goblins are Common, "Most Monsters" are Average, and Novaspawn are Rare.
So how exactly do I make this determination if it isn't a Space Goblin or Novaspawn?
I tried searching various sources online, and most of them indicate that they think it should be done based on some very fuzzy sense of what would be known to the PC based on their background. This is much like the top answer to this 4e question here (which is of course for a completely different system). However, none of those seem to be from official sources, nor do they reference any official sources.
So is there any official guidance on this?