The following are some basic examples of common ways to implement inventories in games. These examples are intentionally minimal and basic; real-world examples of the presented mechanics will probably require a great deal more polish.
Collectibles like medals can be used to enhance and reward player exploration, or as a generic reward for solving puzzles or completing other challenges.
This recipe shows how you can create basic collectibles, and use events to automate rewards for earning collecting them.
This recipe illustrates a very basic crafting and gathering style game.
This recipe shows how to create a basic equipment system.
Key style items are very simple to create and use. Here's an example of the player being able to find an important item that can be used to advance.
Examples of some basic consumable items, like potions that can restore the player's HP.
This recipe shows how you might handle basic buying and selling.