Seat covers for 2015 Prius 4? Recommendations?

If you have airbag in the seat, make sure the cover is weakened there, so it will open. I think if that taken care the overall quality should be good - or rather if that is not wrakened, it’s probably poor quality (or made for seat without airbag).

 

I use Australian sheepskin covers. They make a world of of difference in comfort and have excellent thermal attributes...warm in the winter and cool in the summer. I’ve had them in almost every car I’ve owned. Your average Gulfsream G5’s usually have them as standard fair.
BTW, if you’re a PETA advocate just remember that this particular material is not so dissimilar than the leather seats in thousands of cars.