The first one is the most used commands, /give commands
-do /give @p [Item Name] [Quantity] [Optional]
Example: /give @p cake 1

-if you want to get a custom head, just do
-/give @p skull 3 3 {SkullOwner:[Name]}
Note: You must Do PRECISELY As listed up there!
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The Second one was the spawn commands.
This was usually created when making a map.
The Command Is:
-/spawn [Mobs] [X,Y,Z]
Example:
-/spawn Skeletons 1932.193 5.00000 3.4294
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There are also some Time Commands
These Commands Were Used to change the time of your games.
-/time set [Time Ammount]
Example:
-/time set 5000
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Do not forget there are also a bunch of gamerules!
these command were used to change the game settings of your world.
-/gamerule [Gamerules] [False/True]
Example:
/gamerule DodaylightCycle False
those are used to stop the daylight cycle.
The most used one was /gamerule KeepInventory True
These was used to keep your inventory when dies.
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There are even more includes gamemode Commands where ever you are.
-Gamemode [name] [Creative/spectator/survival/adventure]
Example: /Gamemode RexyCrafts Creative
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YES NEW COMMANDS!!!
The /msg Commands

Example:
/msg [Name] [Message]
These Were Used For In-Game Private Message
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