InControl Mod

InControl is a mod that allows you to change multiple things in Minecraft with the help of a rule system. These rules are located in separate JSON files outside of Minecraft and have to be edited there. List of things you can change: 

• spawn.json: with this file, you can block spawning of certain creatures under certain conditions. In addition, when a spawn is allowed you can also alter some of the properties of the mob like maximum health and others
• potentialspawn.json (1.12 only): with this file you can remove and add spawn rules under certain conditions. The rules in this file are used before the rules in spawn.json are fired so make sure that when you add a rule for new mobs here, the new mobs are allowed in spawn.json
• spawner.json (1.16 or later): with this file you can add spawn rules under certain conditions
• loot.json: with this file you can control the loot that mobs drop when they are killed based on various criteria
• experience.json: with this file you can control how much experience you get from killing mobs based on various criteria

For the showcase, I have used it to spawn mooshrooms that drop diamonds when killed with a stick in the desert. They also drop a lot more experience than before. 

Note: This mod does not do anything on its own. You have to create these rules yourself to make it do something.