Minecraft wiki entry for Spawn, associated text: For zombie villagers, drowned, pillagers, donkeys in savanna biomes, parrots in jungles excluding bamboo jungle and jungle, cats in swamp huts and witches, it is 1.
For parrots in bamboo jungles and Jungle, polar bears, squids in lukewarm oceans, pandas and dolphins, it is 1-2.
For donkeys in plains biomes, ocelots and pufferfish, it is 1-3.
For endermen except in the End and in nether wastes, and squids except in lukewarm oceans, it is 1-4.
For rabbits and blazes, it is 2-3.
For guardians, foxes, zombified piglins in crimson forests and striders, it is 2-4.
For turtles, it is 2-5.
For horses, it is 2-6.
For piglins and hoglins in crimson forests, it is 3-4.
For Cod it is 3-6.
For llamas, it is 4-6.
For mooshrooms, it is 4-8.
For wither skeletons and skeletons, in nether fortresses, it is 5.
For bats and tropical fish, it is 8.
For every other mob, it is 4.