I personally liked the ice mobs a bunch during the old version but I'm not too sure about the new one yet.
Obviously dinosaurs because I my country there is a really awesome dinosaur called 'platvoet' it means flat feet. Lol
Shieeeeet when your childhood hits you like a truck. Crustaceans are arthropods, like bugs so... I guess that works? I'm thinking my favorite mob will still be the Zojira. Can't really beat that thing.