This Addon replaces (Cave) Spider, Enderman, and Skeletons with husks/zombies. The loot from the Zombies is the same as the mob it replaced. It tries to change the game to be more like a Zombie Apocalypse.
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Changelog
Added more details to post about how the addon works and what spawning is like during the day and night.
Update: I ended up making my own mod, it's a lot better than this, simply changes the spawn rules