Minecraft wiki entry for Spawn, associated text: Enderman: During the time that they hold a block
Fish (all variants) and Axolotl: Spawned as a result of placing out of a fish bucket or Bucket of Mob.
Zombie villagers: If they were converted from a villager that has been traded with. This still counts toward the hostile mob cap.[8]
Hoglins: If a crimson fungus is used on them. Zoglins as a result of hoglins have crimson fungus used on them before they zombify also do not despawn.