Java Edition 18w16a

18w16a is the thirty-second snapshot released for 1.13.

General

 * New world type: Buffet
 * Creates single-biome worlds.
 * Allows choosing between Overworld and End terrain generation.
 * Another way to generate chunks (Checkerboard) is available by using an NBT Editor to open a Buffet world's "level.dat", and using the following code for the "generatorOptions": {"biome_source":{"type":"minecraft:checkerboard"}}.

Blocks

 * Coral fans now generate in coral reefs, on the sides of coral blocks.
 * Blue ice is slightly less slippery.
 * Coral blocks
 * Now require Silk Touch to drop as items when mined, otherwise they drop dead coral blocks.
 * No longer instantly turn into dead coral when on land.

Mobs

 * Drowned can now spawn extra in underwater ruins, besides their regular spawning in the oceans.

Gameplay

 * When water spreads and would later turn into a source block, it now immediately just places a source block.
 * Conduit Power particles are now blue instead of orange.
 * Water Breathing given from turtle shells no longer shows particles.

General

 * Optimized world spawn position–finding code.
 * New  block tag for blocks that the player can spawn on.
 * There is now a distinction between scheduled "liquid ticks" and "block ticks".
 * New block and item tags for coral.
 * Changed how the temperature of ocean biomes is calculated; should result in nicer transitions between oceans.
 * Biome names are now translatable.
 * Updated some biome names:

Video
Video made by slicedlime: