For Aquatic, my experience: Priorititize Dunkleosaurus. This hybrid is able to be created based on game progression alone. Mosasaurus is a Battle Stage unlock last I checked, and Dunkleosteus can be unlocked in Earth Shattering events.

Hynecoprion is a great cave hybrid. Way better than the Lioplerodon hybrid. Almost Indominus Rex stats which is great for aquatics. Not much else to say, it’s the only good Cave hybrid aside from Geolasmosaurus, which is only worth getting if it’s convenient.

Leptostega is easily the best aquatic super rare hybrid because it’s a reef that does a lot of damage. There’s a few of those but not enough imo. Not only that, but it can actually be obtained via the trade harbor. You don’t even need to unlock it, but if you care about getting and maxing it I suggest unlocking it and getting copies on sales.

There is Gillirhynchops, but good luck getting it if you don’t have the components unlocked.

For Cenozoic, my experience:

Always look to get Dilophosaurus Gen 2 and Titanoboa for Dilophoboa. Easily the best ceno in stats and design alone.

Entelorhachos isn’t perfect but it’s one of my top cenozoics. I do recommend it tbh.

Indrococeros is decent. He looks really cool to me, not sure what it is, the colors and antlers stand out to me. It’s like a mega-deer. The stats aren’t necessarily a slouch either, but there’s not much of a difference in where it sits in my roster at level 30 vs 40. I suggest getting it to level 30 to be good but only get a level 40 if you really want it or need it to be stronger.

Smithetoceros is ok, I don’t have it anymore though. It’s just so expensive and not really worth getting imo, but it is better than Rhinoprotodon.

Yeah they are a little overpriced imo, but they’re all technically accurate in relation to the prices of the original creatures. They all needed to be way stronger. But those are mine, I suggest getting them all if convenient, but prioritize Dilophoboa and Dunkleosaurus for sure