So I know that kryptonias can purr when they happy just like cats so I couldn't help myself and just have to add some headcanons.
At first I think it would be cute if they have cat shaped pupils. Than I was like... Kryptonias are aliens but they look SO similar to humans. I want to change that a little. That's why I draw Kal with blue blush I think that would be cute. And popular color eyes are blue and lilac among kryptonians no brown or green eyes (or this colors are very rare).
Also I was wondering about their behaviors. It would be cute and funny if they have instinct reactions similar to cats.
For example (superbat example bc I love this two):
Clark do some difficult superhero staff very well. And after JL meeting Batman aproche him and he's like "Good job Kal" and than Superman not only purrs but also rubs his cheek against B's shoulder (just like cat)
I can't stop thinking about this headcanons and possible fluff I could write...