Use a Grindstone to get experience from an enchanted item.

Befriend twenty stray Cats.

Name a Shulker Box with an Anvil.

Use Riptide to give yourself a boost.

Eat nothing but Kelp for 3 days.

Use a Dried Kelp block as fuel in a furnace.

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

Dye your bed a different color.

Poison a Witch with a Splash Potion.

Stay underwater for 2 minutes.

Respawn the Enderdragon.

Kill the Wither.

Kill a mob next to a catalyst