I grew up Mormon in Utah and I don't recall seeing a savory Jell-O salad at any functions I ever attended.

Sweet "salads," usually served as side dishes, are very common, though. My favorite, which doesn't actually include Jell-O, is my mom's frog-eye salad. It's made up of acini di pepe pasta, whipped cream (preferably Cool Whip), and pineapple chunks, mixed with a sauce of pineapple juice thickened with eggs and flour. Yum!