The Tropical Slime; it's a new water slime you could sometimes find spawning in warmer oceans, as well as lakes in jungles, lush caves and mangrove swamps. If your not careful, it's gonna attack you and your axolotls to deal some damage. If you kill it, you can get a bit of experience and tropical fish. If you use a water bucket on a large one, you get a tropical fish bucket. It has 3 sizes but they split into normal slimes when killed, I don't know how to fix it. Axolotls will attack tropical slimes. A frog may eat a small tropical slime, it will drop a tropical fish if it does.

The Lobber Zombie; it sometimes spawns instead of a normal zombie, but it's more common then a zombie villager. If you come to close, it has a melee attack which deals 3 damage and gives hunger for 10 seconds. At a distance, it could attack you with rotten flesh to deal 3 damage and give a weakness effect. They are hostile to villagers and iron golems too, and will burn in the sun like some other zombies. With a smite sword, you could kill them more easily. They drop the same items as other zombies, but drops more rotten flesh on average.

The Bouldering Zombie; it is located at night time in the extreme hills biome, as well as the stony peaks mountains (ones with calcite). This zombie moves faster and hits harder then your average zombie and has superb jump skills, being able to sometimes make enormous leaps and also climb up blocks like spiders, so towering up against them may not be advised. They can drop rotten flesh alongside some stone and cobblestone and 5 experience on death.

The Bone Spider; it can be found frequently below y level 0, where deepslate is found everywhere. It has a melee attack that deals 8 damage and 10 seconds of wither effect, but at a distance it shoots bone shards that deal 5 damage. Like other undead mobs, they can't drown and will burn in the sun. You can kill them easily with the smite or bane of arthropods enchantment. On death, they drop 10 experience and also bones, bone meal and string. They can also spawn being ridden by skeletons so... watch out for that.

The Viler Witch; it rarely spawns in place of a regular witch, the best place to look for witches and viler ones will be the swamps. It has 3 different attacks: shooting lingering poison acid, shooting fireballs and summoning witches. However, they don't use potions like normal witches, but can call nearby witches to come and attack mobs they are angry at. If you kill it, you could get 20 experience points and the same items as a normal witch, but in higher quantities, and also sometimes lapis lazuli.

The Skeleton Wolf; often, it spawn in the soul sand valley biome in the nether. It behaves a bit like a wolf, but is always hostile to you and can't be tamed. It's melee attack deals 4 damage to you, rabbits, baby turtles, llamas, sheep and foxes. Occasionally, it also howls, which hurts you and other mobs for 6 damage, but doesn't hurt skeletal mobs and gives them a strength effect for 10 seconds. There are even juvenile variants of skeleton wolf, that are smaller and spawn less often. But unlike the adults, they have not learnt how to howl yet, this makes them less dangerous. Like wolves, hurting one makes them all angry at you. Again, the smite enchantment can kill them easily. Killing it gives 5 experience and bones.