Number 10 on my most wanted list is Tupandactylus/ Tapejara. Due to the prevalent theory that these were frugivorous animals, it would be the first herbivore among the pterosaur roster.
Number 9 on my list is Concavenator. Since Altispinax is controversial as to whether it existed, I support MushroomSock's stance of changing it to Concavenator
Number 8 is Edmontosaurus. As a crestless hadrosaur, it would stand out from Parasaurolophus and Lambeosaurus quite well..
Number 7 goes to Arctodus. I've always loved bears, and Arctodus is the coolest of them all in my opinion.
Number 6 is Isotelus. Imagine it being released on April Fools. We Added I.rex. All the hybrid wanting people think that they're getting Indominus, only to receive a trilobite. As for the rest of us "A surprise to be sure, but a welcome one."
Number 5 is Xiphactinus. Ever since I first saw this fish's fossils at the Science Museum in my home state as a child, I was in awe of it. Its size. How it looked so intimidating, and its sleek body giving me images in my mind of this beast darting through the cretaceous oceans.
Number 4 is Glyptotherium. I know Doedicurus is more popular due to its tail club, but due to Ankylosaurus already being the true king of the club, I find Glyptotherium to be a more suitable choice.
Number 3 is Pulmonoscorpius. So far the only unconfirmed member of the iconic Carboniferous big bug trio (Arthropleura, Meganeura, Pulmonoscorpius), and my personal favorite of the three.
Number 2 has to go to Megatherium. While [Redacted] is currently already in the mod, a true ground sloth would be a perfect addition to the mod.
Finally, number 1 is Macrauchenia. I adore these goofy looking weirdos, and always will.