I have added added Vanilla Command Block Modifications to my world.
-Buy: Crafting Stations, Building Materials, Ore, Food, Tools, Weapons, and Armor.
-Sell: Wood, Resources, Food, and Loot.
-Killer Rabbit Jockeys when a Zombie gets close to a Rabbit,
-ZombiePigmen spawn in the Overworld when a Zombie gets close to a Pig,
-Slime Zombie when a Slime gets close to a Zombie,
-CaveSpider when Skeleton gets close to a spider,
-Mooshroom when a Cow walks on Red Mushroom,
-Creepers and Villagers are struck by Lightning if you get too close ,
-Endermen spawn Endermites if you get too close,
-Zombie or Skeleton Horse when a Horse gets close to a Zombie or a Skeleton.
Mob Effect Features:
-Bat gives you health boost.
-Sheep gives you Regeneration for 60 Seconds
-Pig gives you stength for 30 seconds.
-When you jump on a Slime you Bounce.
-Zombie gives you Weakness/Slowness if u are close.
-Skeleton gives you Weakness if you are close.
-You can detect Enderman within 20 blocks, gives you Haste.
I am going to continue to add commands and features using all vanilla commands and command blocks (ie. Custom Villagers, more Custom Mobs, And a SafeSpawnPoint.). I want to open the world to players. Just send your IN GAME NAME and I'll send you an invite.