Let's talk Passive items. These are items that are not selected and used as a B (or A) button item but still passively in your inventory. Nevertheless, they can still be extremely useful. The most common of passive items are bomb bags, quivers and wallets. But they can do so much more, even if you can't actively use them as a weapon.
Here are some ideas I have for my own passive item:
-Lucky Clover: This is used in conjunction with a custom shovel item I made. The shovel can dig up dirt (obviously), causing items to sometimes spawn, based on a random "chance." The drop set by default includes only hearts, rupees, and seldomly, blue rupees, plus a 40% chance of digging up nothing. After collecting the Lucky Clover, the drop set changes these chance numbers so that you have a greater chance of spawning something and adds other items you can dig up too, including small magic jars, single arrows, and seldomly fairies. The chance of spawning nothing is reduced to 20%.
-Zora Scale: I've discovered a way to script not being able to dive in water, even while you have the flippers, until you get a certain item. This is that item. When you get the flippers, you can swim but your A button, the button that lets you dive, is disabled until you get the Zora Scale, then you can dive.
-Protective Scarf: To be honest, not sure what to call this, may change the name. But this is also a swimming-related item. In certain bodies of water, Link will freeze periodically (every few seconds or so) and take damage because the water is too chilly. Once you collect this item, you can swim in this water, free of being frozen and damaged.
-Bombchu Container: Not really much different than the bomb bag but thought I'd mentioned it here nonetheless. This allows you to carry Bombchus, mouse-like creatures that walk around until it hits something solid or an enemy and then explodes.
I'd love to have three or four other passive items in my quest, even if they're just optional items used as rewards.