I'm excited to share my ideas for whoever is reading this thread, i hope you like them:
.Willow Trees should be generated in swamps. The willow trees could also come with saplings, willow tree wood and stripped willow tree wood.
.Hippos are suggested as a great idea, they spawn in swamps and when you attack one, it will come charging at you at the speed of the player sprinting. They will chase you until you have died. Adult Hippos can also be spawned in swamps; they are 2 blocks taller and wider than normal hippos with a fully grey skin. Adult hippos have the same personalities as normal hippos except they can destroy shields even with thorns on them.
.Grizzly bears are mobs that spawn in the taiga forests, female grizzly bears will have a slightly lighter, coloured fur than males.
.There should be such a thing as Wither bones or Wither skeleton bones, if you tame a wolf with these bones, their fur will change to the colour of black.
.I thought of a great idea, and that's called "A Lapis Golem", This golem is constructed the same as an iron golem but with lapis blocks and the head is a Jack'o lantern! The appearance for this golem is a wide, fat torso with long arms, tiny legs and a villager-like head. The golem's eyes are yellow and glow in the night. The whole body is made out of lapis and it can only be damaged by getting mined by a pickaxe.
.I'm also thinking of a hostile mob called "Brood" , their appearance is a grey zombie wearing a wooden mask and damaged miners clothes holding a stone pickaxe. These mobs will attack golems, villagers and players with their pickaxes.
.Metal shields can be the upgraded version of shields, they are stronger and last very long even when digging with it, Adult Hippos cannot destroy Metal shields. These shields can be made combining a normal shield with any enchanted unbreaking book using an anvil.
.I thought of the idea of "Scorpions" which spawn in desert biomes, they look like small grey scorpions which give you poison when they sting you. Ancient scorpions could also spawn in desert biomes, an ancient scorpion's appearance is the same colour as a normal scorpion but 3x bigger and it has cracks and vines all over it. The ancient scorpion will not just give you poison but also weakness when it stings you.
This is all the ideas i could think of, thank you for reading this
When posting suggestion threads, you are only permitted to include one idea (or closely-related group of ideas) per thread. This thread contains multiple unrelated ideas and is considered a wish list, which is not allowed.