Me, too. We just bought a blue one. No fancy patterns on the liner. Basic blue.
It seems to me that the point of a pool is to hold water, so you can swim. How do fancy patterns contribute to that?
I wouldn’t have been surprised if dark pools were a trend, like black countertops and appliances. However, my nextdoor neighbors have a pool with a dark gray/black interior, and she told me that last summer, the black surface made the water so warm that it was like a giant hot tub ... not what you want when evening temperatures are in the 90s.