Feed a dolphin raw cod and have it lure you to treasure.

Place four Sea Pickles in one block.

Using the Frost Walker boots, walk on at least 1 block on frozen water on a deep ocean.

Place 9 fully explored, adjacent Maps into 9 Item Frames in a 3 by 3 square.

Tame a Horse.

Dry a Sponge in a Furnace.

Kill the Wither.

Eat a Notch Apple.

Spawn the Wither.

Gain the trust of an Ocelot.

Create an Iron Golem.

Smelt wood trunks using charcoal to make more charcoal.