To craft a spawn egg you will need at least 1 diamond. Different entities require more or less diamonds to craft depending on their size or rarity. I tried to balance the recipes as much as possible, if there are any issues or suggestions you are free to contact me on twitter @MitchD_03 

Below are all the recipes used to create spawn eggs and the monster spawner.

First off is the recipe needed to craft a monster spawner:

In the center of the monster spawner is a new item called a spawner token. This token can be crafted using a nether star or ender dragon egg, but is also able to spawn in chests which are located in end cities. Here are the recipes of the spawner token:

Here's an example of how a spawner token can generate inside an end city chest:

Here are the crafting recipes for the spawn eggs:

Some of the recipes contain more of each item than is required. You will only need ONE of each item shown in these recipes.

Recipe for the bat spawn egg:

Recipe for the blaze spawn egg:

Recipe for the cat spawn egg:

Recipe for the cave spider spawn egg:

Recipe for the chicken spawn egg:

Recipe for the cod spawn egg:

Recipe for the cow spawn egg:

Recipe for the creeper spawn egg:

Recipe for the dolphin spawn egg:

Recipe for the donkey spawn egg:

Recipe for the drowned spawn egg:

Recipe for the elder guardian spawn egg:

Recipe for the enderman spawn egg:

Recipe for the endermite spawn egg (You can place the diamond and ender pearl everywhere on the crafting table):

Recipe for the ghast spawn egg:

Recipe for the guardian spawn egg:

Recipe for the horse spawn egg:

Recipe for the husk spawn egg:

Recipe for the llama spawn egg (you can use any color carpet here):

Recipe for the magma cube spawn egg:

Recipe for the mooshroom spawn egg (must be the red mushroom):

Recipe for the panda spawn egg:

Recipe for the parrot spawn egg:

Recipe for the phantom spawn egg (I really don't know why you would spawn them :P):

Recipe for the pig spawn egg (Oink!):

Recipe for the pigman spawn egg (Not oink!):

Recipe for the polar bear spawn egg:

Recipe for the pufferfish spawn egg:

Recipe for the rabbit spawn egg:

Recipe for the salmon spawn egg:

Recipe for the sheep spawn egg (Can be any color wool):

Recipe for the shulker spawn egg:

Recipe for the skeleton spawn egg:

Recipe for the slime spawn egg:

Recipe for the spider spawn egg:

Recipe for the squid spawn egg (#bringbacksquidmilk):

Recipe for the stray skeleton spawn egg:

Recipe for the tropical fish spawn egg (Must be coral block but can be any color):

Recipe for the turtle spawn egg:

Recipe for the villager spawn egg:

Recipe for the witch spawn egg (Must be potion of instant health 1 (they drop them)):

Recipe for the wither skeleton spawn egg:

Recipe for the wolf spawn egg:

Recipe for the zombie spawn egg:

Below are the new recipes added in version 2.0: 

Recipe for the Bee spawn egg: 

Recipe for the ocelot spawn egg:

Recipe for the fox spawn egg: 

Recipe for the glow squid spawn egg:

Recipe for the strider spawn egg:

Recipe for the hoglin spawn egg:

Recipe for the piglin spawn egg:

Recipe for the zoglin spawn egg:

Recipe for the piglin brute spawn egg:

Recipe for the goat spawn egg:

Recipe for the axolotl spawn egg:

Recipe for the allay spawn egg:

Recipe for the frog spawn egg:

Recipe for the pillager spawn egg:

These are all the recipes of the spawn eggs! If you need help or anything else contact me on twitter @MitchD_03. Have fun with this addon!