The zombie horse and the giant have sat unused in Minecraft for years now,this aims to fix that.

Giant:

• Spawns instead of zombies above y=60 rarely, after getting the advancement"Zombie Doctor"
• Deals damage in a small radius around itself, and can leap into the air and slam into the ground, launching nearby players, also spawns a few zombies when it lands.
• Once low enough, gets resistance 3 and spawns a horde. Giants have natural projectile protection, but bows still work pretty well.

Summons zombies, husks, drowned, and occasionally,

Zombie Horsemen:

• Have chainmail armor and an iron sword
• Spawn riding Zombie Horses (tamed)
• The giant drops a lot of rotten flesh and apples, as well as uncommonly golden apples, and rarely, enchanted golden apples. Once defeated, another giant cannot spawn until a while has passed. (~50 minutes)
• If you want to spawn a giant, don't summon it, spawn a zombie and use this command instead:/execute as @n[​type=minecraft:zombie] run function giant:giant