Since the Crystal Desert will be coming in the (possibly near) future, I figured I'd make a few Slime recommendations if the developers don't have any new Slimes for the area yet (although they most likely do). Sorry the images are so large.
First up is the Camel Slime! Its diet is Veggies, and its favorite food is the Carrot. It's passive unless it has just eaten. It would be mildly rare in the Crystal Desert, appearing less often than other slimes in the environment. It will spit at a nearby rancher if it has recently eaten, dealing 10 damage and leaving them with a bad scent that is repulsive to other slimes; but on the bright side, it can go a day or two without being fed, as it stores food in the hump on its back, but it will not produce Plorts whilst relying on its hump. Its Plorts would be worth around 30 Newbucks before market changes.
Second is the Tumble Slime! Its diet is Fruit, and its favorite food is the Prickle Pear. It's passive, but deals 5 damage to ranchers when touched. It would be very common in the Crystal Desert, being the slime that appears most often, making the desert a tough area to venture through. It is covered in small thorns and is very light, making it easily blown about by the wind and possibly into exploring ranchers. Its Plorts would be worth around 15 Newbucks before market changes.
Lastly is the Cactus Slime! Its diet is Water, and its favorite food is... Wa-water. *ahem* It's passive, but deals 5 damage to ranchers when touched. It would be fairly common, appearing often in the Crystal Desert, but less often than Tumble Slimes. After 12 in-game hours, it will sprout a flower; 12 in-game hours more, and the flower will become a Prickle Pear! Unfortunately, it will not produce Plorts when put into a Pond, so it must be manually given water from spouts on the Far, Far Range. Its Plorts be worth around 20 Newbucks before market changes.