Minecraft 1.15 has not been released yet, but this idea is dubbed The Game Changing Update. This update included all the new textures and added four new bosses and three new dimensions. The update added furniture, colored planks and other community asked features. The game also added some new things like hydration and irrigation systems for farms and sinks/toilets/tubs.
Sky Island Dimension
The sky island dimension is a dimension gotten too by creating a portal out of Iron and Gold blocks in the same pattern as a nether portal, making the gold blocks corners and middle parts and iron blocks being every other space.
Shark: Spawns in the deep ocean, attacks players. Has 50 HP and deals five hearts of damage each hit. They are very rare and drop various fish and shark teeth, which can be used to craft the mega-trident.
Bear: Spawns in Taiga Biomes, Forest Biomes, and Snow Biomes. It has a 20% chance of spawning and deals 3 hp every hit. It has 20 hp. When killed it drops hide, which can be used to craft hide armor. It also drops bear meat. They can be bread with blueberries or fish. They can be tamed with fish and attack mobs if you attack them. You can create three stages of bear armor, iron, gold, and diamond.
Panda: Spawns in the Bamboo forest biome. Has 25 hp and doesn't attack the player unless attacked. It will grow hostile if you attack its babies. They can be bread with bamboo.
'Aquatic Snatcher (Mob A)': Spawns in the deep ocean. Has 25 hp and deals 2 hp every hit. It can latch onto you and drown you. It has a 21% spawning.
The Great Hunger (Mob C): Spawns in every biome except for the ocean. Doesn't attack the player, but instead eats dropped items.
Hovering Inferno: (Mob D) Spawns in the nether. Has 120 hp and deals 20 hp every hit. Has a 2% chance of spawning and only spawns in Deep Nether Fortresses.
Rattle Snake: Spawns in deserts, makes a rattling sound when you get too close. Has 5 hp but gives you Posin 3 and deals 4 hp.
Hornet: Hornets are small and can fly. They spawn in forest and dark forest biomes and gather around their hive. If the player gets too close, they chase the player. If the player breaks the nest, 20 hornets fly out and chase you. Each one has 2 hp and deals 2 hp every sting.
Mummy: The mummy spawns in the desert temple and roams around. They have 10 hp and deal 3 hp. They drop gold ingots.
Pharoh: They spawn in the desert temple and protect the treasure room and can hypnotize the players tamed pets and animals. They have 22 hp and deal 5 hp. They attack the player with a spear that they drop when killed.
Pirate: Pirates spawn in pirate ships. They attack you with iron swords and have 15 hp. They deal 7 hp. When killed they drop a random item from the games item list.
Elephant: A giant assertive mob that walks around the savannah biome. They only attack if attacked and can be bread with grass. It has 30 hp and deals 5 hp.
Lion: The male lion is an aggressive mob that attacks the player if it sees you. The female lion stays back and protects her cubs. In order to breed, you need a female lion and male lion. They can be tamed and will follow you and attack things that attack you or you attack. It deals 10 hp and has 15 hp.
Ghost: Spawns in the Haunted Forest. They can only be killed when they turn light blue and start attacking you. They have 10 hp and deal 2 hp of damage. They can go invisible for 16 seconds, but they can only deal 1 hp damage when invisible. They drop ghost essence when killed and can be trapped in a bottle if the player is quick enough. They can turn this into a splash potion and trap the ghost in a ghost cage built out of ghost proof glass and titanium blocks, or this can be used to summon in the reaper ghost.
Zebra: Spawns in the savannah biome. They have 10 hp and are very passive.
Giraffe: Spawns in the savannah biome. They have 12 hp and only attack if attacked.
Alligator: The alligator spawns in swamp biomes and has 12 hp and deals 8 hp. They drop alligator teeth which can be used to build the Mega-Sword.
Turkey: Can spawn in forest biomes. Has 4 hp and does not attack the player. It drops feathers and raw turkey meat.
Fox: Has 10 hp and attacks chicken, turkey, and rabbits. They can be bread with raw chicken, turkey, or rabbit meat.
Deer: Has 10 hp and does not attack anything. They can be bread with grass. They drop Venison and Animal Hide.
Bighorn Sheep: A sheep that spawns in valleys. They have 12 hp and only attacks if attacked. They deal 4 hp every hit and drop animal hide and wool.
Slime Lord: Spawns in Slime Dungeon. It has 80 hp and deals 6 hp every hit. It acts as a normal slime, but has a blue and red cape. He spawns smaller slimes every 15-21 seconds. It drops slime armor, which stops swords from hitting because they get stuck in the slime. This only works the first two hits with the item the player is holding.
Giant Zombie: The giant zombie spawns in Zombie Villages, which can be found in any biome that spawns villages, and can be found in any village variation. It has 150 hp and deals 18 hp every hit. The kicks it's opponent at a long distance. Not only will the player take the damage, they will take fall damage as well. The Giant Zombie drops the zombie arm which deals 23 damage.
Elder Witch: The Elder Witch spawns in Witch's huts at a few dozen blocks away from swamp villages. They are far enough away to still see the village. They have 220 hp, and deals 8 damage, but throws every type of damaging potion in the game. They were villagers that were given a gift, witch-craft. The villagers thought they were too different and casted them away. They grew old and kidnapped villager children and trained them to become witches. The Elder Witch drops the witches rob, which has 21 defense.
Red Dragon: Spawns in the sky dimension. It has 550 hp and deals 10 hp every hit. It flies from island to island. When it lands it covers the entire island with fire and flies to the next one. The player has to travel island to island until the dragon grows tired. Then the player can hit it with everything they have. It drops the everlasting sword, which is a sword that never gets destroyed and can deal 50 damage. They also have a 25% chance of getting 1 Red Dragon Scale. It can be respawn by placing an obsidian block on the obersvers on each of the islands.
Death Shark: The Death Shark is a shark mob that spawns in the deeper ocean and has 1,500 hp. It is recommended to take on after the Red Dragon due to the Red Dragons drops. The Death Shark can swim up to 10 blocks a second and deals 20 hp a hit. When killing it, it drops the mega-trident which deals 120 damage and does not lose durability for the first 250 uses. Then it can be used for 9,999 hits.
Ghast King: The Ghast King is a boss that is spawned in the nether by crafting the spawn egg. The spawn egg can be crafted by using 3 ghast tears, 2 Red Dragon scales, and 1 bucket of lava in this pattern. This boss acts similar to a Ghast, but launches more explosives more quickly. It is much smaller to move through caves quickly and has a crown. It has 2,000 hp and drops the magma blade which deals 500 damage.
Reaper Ghost: Can be summoned in the secret basement of the Woodland Mansion. It has 400 hp but rarely does it go vulnerable so you'll want a powerful weapon to kill it quick enough. It is recommended to have at-least the Mega-Trident or a higher weapon if you want to beat it efficiently. It drops the ghosting sword, which deals 400 damage but can grant the user invisibility for up thirty seconds at a time, but it has a cold down time of twenty seconds. It also has a 10% chance of dropping the ghosting armor, which makes the user invisible as long as they have the armor on. Even the armor weapons and potion particles are invisible.
The Ender Dragon: Now has 250 health. Her breath is instant kill unless you have magma armor or higher. It is immune to any sword below Diamond and is immune to bows. These changes were made to make the ender dragon a real final boss. The egg will now hatch in 12 in-game days if not removed from the end. The ender dragon will also now drop 500 levels worth of XP.
The Wither: The wither can now only be spawned in the nether fortress basement. It drops the wither sword and the nether rack pickaxe (20% chance). Now has 350 health.
Haunted Forest: A forest full of dead and dark trees, and it is night all the time. Dark wood and dead wood can only be found in this biome, and those can be crafted into black wood planks, black wood plank stairs, fences, half slabs, fence gates, pressure plates, trapdoors, and buttons. Torches don't work in this biome so you have to rely on your instincts and your map. Ghost spawn in this biome and are a standard hostile mob in this biome. The ghost village can spawn in this biome as well. Ghost also spawn in the Woodland Mansion along with the other mobs. Glow-stone does work, and every 500 blocks on the path there is a small glow-stone lamppost. Many gravel paths run through it leading to the woodland mansion, which is just outside of the village. The village contains two blacksmiths, one old church, one library, one butcher's shop and 21 houses. It contains many dangerous mobs mostly because it is always night so mobs can spawn whenever they want. Woodland mansions are found in these biomes as well. The Dark Forest is no smaller than 100,000 square blocks, and there is usually only one or two for every world.
Enchanted Biome: The enchanted biome is a biome where it is always day. It is the opposite of the dark forest. Hostile mobs don't spawn, and can't enter the biome due to its force field. The water in this biome heals you, so you can bucket it up and take it home. It cannot be used to make an infinite water source. The enchanted biome is usually 2,500 square blocks, much smaller than its dark counterpart. Every tree in this biome is a cherry tree, which grants you cherry planks. They are the color red. You can create other wooden things with the wood.
Volcano Biome: The Volcano Biome is a biome with the volcano block. It is a dark grayish brown stone. The volcano has a large hole in the top that leads down to the magma chamber. Volcanos have a dungeon inside, that can contain any amount of rare loot. Animals can't spawn in this biome, and any tamed animal will be to scared to enter this biome. You are on your own.
Bamboo Forest: The home of the Panda. The bamboo forest only has bamboo trees, which means when you cut down any part of the tree, the whole thing comes down. They can be used to breed pandas.
Deeper Ocean: The deeper Ocean goes even deeper than the deep ocean, reaching down to bedrock. It is so dark down there you can't see more than one block in front of you. Death Sharks spawn there.
Flatlands: The flatlands is a biome that is entirely flat and doesn't have one block too low or too high. It is great for creative and survival builders. Usually it is 10,000 square blocks.
Valley: Valleys are biomes that go down to level 4. They have Valley villages, which are normal villages but are maple instead of oak planks and logs. Valleys have vains of above ground ores due to most of theme being below level 40. Lions spawn in this biome along with Foxes, Deer, and Bighorn Sheep. Valleys also are more likely to contain Copper and Tin.
Desert Biome: It is impossible for water to spawn in this biome, and it is impossible to border any biome other than Savannah. Desert temples are now 10x the size and have an entire underground maze full of guards. Rattle Snakes can now spawn in the desert as well.
Savannah's: They cannot border snow biomes or ocean biomes. There is a 10% chance that water will spawn in this biome. They are now much bigger than usual and can be no smaller than 20,000 square blocks. Acacia trees are 5 blocks taller.
Forest: Pine, Apple and maple trees can now spawn in the forest.
Plains: Water pools are less common, but rivers are more common. Maple and Pine trees can also spawn in plains now.
Jungles: Jungles are now much bigger, and they can be now smaller than 5,000 square blocks. Jungle temples now have a 70% chance of spawning and jungle tree houses have a 5% chance of spawning.
Green Apple Sapling
Red Dragon Scale
Animal Chest Plate
Animal Leg Armor
Everlasting Leg Armor
Titanium Leg Armor
Shark Spawn Egg
Bear Spawn Egg
Panda Spawn Egg
Aquatic Snather Spawn Egg
The Great Huger Spawn Egg
The Hovering Inferno
Rattle Snake Spawn Egg
Hornet Spawn Egg
Mummy Spawn Egg
Pharoh Spawn Egg
Pirate Spawn Egg
Elephant Spawn Egg
Male Lion Spawn Egg
Female Lion Spawn Egg
Ghost Spawn Egg
Zebra Spawn Egg
Giraffe Spawn Egg
Alligator Spawn Egg
Fox Spawn Egg
Deer Spawn Egg
Big Horn Sheep Egg
Death Shark Spawn Egg
Ghast King Spawn Egg
Reaper Ghost Spawn Egg
Iron Bear Armor
Gold Bear Armor
Diamond Bear Armor
Iron Dog Armor
Gold Dog Armor
Diamond Dog Armor
Titanium Crossbow Bolt
Pine Fence Gate
Pine Pressure Plate
Maple Fence Gate
Maple Pressure Plate
Cherry Fence Gate
Cherry Pressure Plate
Black Fence Gate
Black Pressure Plate
All Other 15 Colored Planks, Stairs, Slabs, Doors, Fences, Fence Gates, Trapdoors, Buttons and Pressure Plates
Claw Foot Tub
All 16 Colored Bricks and their Stairs and Slabs
White Blaze Rod
Iron Bar: Iron bars have seen some design changes, they now looks like this:
Glass: Each block is completely smooth and when blocks are placed next to each other they connect and the edges are removed on the sides that are touching.
Deep Nether Fortress
None Item/Block/Mob/Boss Addition
Hydration System: You get thirsty as you run and punch and do things. Water increases your hydration by a lot.
Tutorial World: Teaches players how to play the game.