Blocks
Mobs
Dimensions
Items
Structures
100

Which is the 2nd dimension

the Nether

100

Which 2 structures holds Pilligers 

Woodland mansions and Pilliger outposts

250

Which mob is in all 3 dimensions

the endermen

500

Which mob is a dinosaur

the Sniffer

9999

What is the rarest Block in MC

The Snowy Grass Block

9999

What is the rarest mob in MC

Zombie Villager Jockey with full enchanted diamond armor and an enchanted iron sword, left-handed, and wearing a pumpkin on Halloween

9999

What is the Dimension only in the April fools snapshot 

the infinite dimension 

9999

the only thing you can get a grass block by

a pair of shears with silk touch

9999

what is the rarest structure

The rarest naturally spawning structure in Minecraft is a giant brick pyramid, also known as a monolith, found in the Minecraft InDev version. This structure is found approximately 500 blocks southeast of the spawn point in InDev worlds. In more recent versions of Minecraft, the rarest naturally spawning structure is a fossil with diamonds. Fossils themselves have a low spawn rate, and the presence of diamonds further increases their rarity.