My 3 year old says Triceratops, Ankylosaurus, Stegosaurus and Parasaurolophus. Me, I'm just surprised and amused that me can remember and name so many complicated dinosaur names at that age.
I like the titanosaurs in general - they look at the same time majestic and goofy. Like Patagotitan mayorum:
and Udelartitan celeste:
As far as I know the P. mayorum was the biggest land animal to ever exist, as it could reach up to 30-something metres. The U. celeste is smaller, "only" 16m long.
Fun fact: the trees in the artistic rendition of the U. celeste are likely close relatives to this one from my banner.