I’m going to cheat here a bit.
Dio has proven to be surprisingly versatile and while it’s never guaranteed a victory, a straight 15/15/0 Dio hits like a freight train and will 9/10 put everything it’s up against in a really bad spot by the time it’s taken out.
Tenontorex has come to be very reliable with a decent Stun resistance and a great kit. Coupled with the fact that it can hit like an avalanche, it’s a fantastic counter to Scorpio, and does incredibly well against Hadros and Cera, while only fearing a faster Gorgotrebex and Mortem. It’s also not half bad against Testacornibus, though not a guaranteed victory.
Mammolania for pretty much the exact same reasons as Tenontorex, sans against Testacornibus, unless the Testa is in a significantly weaker position.
Erlidominus hails from my OG team after I maxed out Indoraptor back when Indoraptor was still relevant but starting to drop out. The Revenge Cloak only made it more powerful and given that the Dodge mostly works, it’s generally going to one-shot whatever’s in it’s path and my Erlidominus has probably the highest KO count of any creature on my team. It’s going to stick around a bit longer too, but I might be looking to switch it out at some point in the future sadly.
Grypolyth has proven to be a pretty vital creature to have against the likes of Ceramagnus and other powerful Resilients. It’s also proven to be kinda decent against Scorpios, surprisingly, and has on occasion taken down a few Cunnings (or at least seal their doom).
Most of all, I love the designs for all 5. Tenontorex genuinely looks like a real hadrosaurid, though for its sheer bulk it would easily rival Shangtungosaurus as the largest hadrosaurid, while Mammolania and Diorajasaur just straight up look like creatures I would make in Spore if I could, same for Grypolyth while I’m at it.
And I really wish Erlidominus would be adapted into the movies, if only because it would work really well as a horror movie monster of sorts.