Mobs can be hostile, neutral, or passive. They can have special abilities, like piercing through blocks, but sometimes those Mobs do not spawn at all. Mobs ALWAYS spawn in a specific light level.
Passive mobs
Passive mobs cannot attack you, because passive mobs cannot attack players. Even if you do attack them, they still remain passive.
Sheep
Sheep are passive.
Sheep can breed, all you need is seeds, or wheat, which also tames it.
They have 8 hearts, or 4 on-screen hearts. This equates to 40% of a un-armed Minecraft player
Behavior: Eats grass periodically to turn grass into dirt, can be sheared to gather 1-2 wool blocks.
Camel
The camel is passive, being ridable by 2 players, also is tamable.
The camel is also special in a way that it can jump up to 13 blocks, as well as not damageable by most undead mobs.
They get 2 health points each time they are fed a cactus
Bat
Passive, cannot do damage, and can hang on blocks. equates to 60% of a player
Hangs around dark caves, as a bat.
Axolotl
Passive, has 14 half-hearts, aka 7 hearts. They inflict 2 damage when damaged by mobs. This only happens when the axolotl is damaged by a mob. There is a 0.01% chance that the blue axolotl spawns. It is extremely rare, with a 1 out of 10,000 chance of spawning blue.
Allay
Has 10 hearts, and is passive. Spawns in woodland mansion cells and pillager outpost cells. Like all mobs, if it holds a totem of undying, if it dies, it will regain health upon death, as well as the totem breaking. Can hold items, and it will be tamed with cookies. When holding an item it will scavenge for it.
Cat
The cat is passive, only dealing 3 points of damage to rabbits and baby turtles. It has 5 hearts and is tamable by using raw or cooked cod. They can scare creepers, too.
Chicken
A chicken has 2 hearts, and can be spawned with a 12.5% chance when throwing an egg. Also, it can be breed with wheat seeds, beetroot seeds, melon seeds, and other seeds. Unlike most mobs, it is one block high and cannot spawn in 1 block areas.
Cod
Cod hold in possession 1 1/2 hearts, and can be picked up by right-clicking it with a water bucket, or you could just interact with the water bucket.
Cow
Needs space to spawn, since its hitbox is 2 blocks high. You can use a bucket on it to swap it for a milk bucket. It can also spawn when you shear a mooshroom, or moogus. 5 hearts.
Donkey
Can hold chests, and is tamable with wheat, apples, golden apples or carrots. You can use a lead on it. 7.5 Hearts
Fox
Has 5 hearts in java edition, has twice the amount in bedrock. runs around and sometimes can hold an item while doing so. Tamable with berries. They jump when seeing a chicken far away from it, because dinnerbone was its prey.
Frog
They can spawn in swamps and mangrove swamps. ]
It spawns above grass blocks and in jungle biome