Be near a Crafter when it crafts a Crafter

Dry a Sponge in a Furnace.

Name a Shulker Box with an Anvil.

Use a saddle to ride a pig, then have the pig get hurt from fall damage while riding it.

Create an Iron Golem.

Defeat an Evoker.

Use a Wind Charge to launch yourself upward 8 blocks

Kill the Enderdragon.

Enter an End Portal.

Unlock a Vault with an Ominous Trial Key

Acquire 30 Emeralds by trading with villagers or mining.

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

Poison a Witch with a Splash Potion.