Removed Herobrine
This flower had its sprite changed to match its real-world namesake.
Rose
On the surface, these spawn most often on a full moon and not at all during a new moon.
Slimes
The newest tree.
Mangrove
Pistons
Beta 1.7
As I like to call it: Water killer 9000.
Sponge
Something you weren't able to do with minecarts when they were first introduced.
Ride Them
The hidden "Killer Bunny" mob is a reference to what film?
Monty Python and the Holy Grail
This block's pulling you down with the undertow, son!
Magma
Striders
1.16
Indeed it's a Portal reference, not just food!
Cake
Bedrock level is now de-VOID of this graphical feature, which was cut due to performance issues.
Void Fog
Slimes of sizes 1, 2 and 4 spawn naturally, but can be added (using commands) to be as big as this number.
256
Just like the real-life summertime snack, minus the "water."
Melon
Snowfall
Alpha 1.2.0
Blocks that are this have the face of a Mob inscribed onto them.
Chiseled
Though never functioning in-game, these place-able mechanisms were the precursor to redstone.
Gears
Mooshrooms are cows possessed by mushrooms, mirroring the effects of this real-world parasite.
Cordyceps Fungus
You used to only be able to get this in places with monster spawners.
Mossy Cobblestone
Cobblestone
Cave Game Tech Test
Infdev versions would spawn massive pyramids made of this block.
Brick
Studded armor got the axe! But its sprite was reused from this pre-minecraft Notch game.
Legend of the Chambered
You could say this mob is like a bat out of hell. Well, only if you want all the achievements.
Ghast
It real life, this animal would be sterile.
Mule
Nether Brick(s)
Adventure (or 1.0)
This block slowly changes color over the course of a minute, and then turns back after another.
Prismarine