Here's a list of inventory items from 2004 (some of which could be upgraded or had toggles). I've excluded items that were temporary

*bank card - deposit/withdraw from ATMs, was particularly important because you'd lose gralats when you died.
*Bomb - Toggled with the upgrades of super bombs (much larger explosion) and jolt bombs (regular explosion range, but more powerful and shaped like lightning)
*Bomb Bag - Used to hold bombs.
*Bow - Toggled with the upgrades of fire bow and nukeshot. Fire bow dealt the same damage but created a bomb explosion, and nukeshot delivered more damage, also with a bomb explosion.
*Bruges Bird - Caused the player to go into the hurt gani with 0 damage; also picked up items/gralats.
*Clock - Told you the time
*Crystal Ball - I forget
*Fishbowl - Used to hold a fighting fish, which could be used to fight other fighting fish.
*Hammer - Smooshed players. Was upgradable to 3 levels, with each level being able to hammer an additional type of stake.
*Mace - would swing around the player in a circular manner. Didn't really do well at hitting other players or enemies probably due to the hit box being poorly designed.
*Pizza Stack - Pizza Team guild item.
*Quiver - Used to hold arrows.
*Rat Form - Identical to present Rat Morph.
*Shovel - Three levels of shovel, each level allowed a new type of terrain to be shoveled (grass, snow, lava)
*Torch - Lit up an area. A few hits would set other players on fire which would drain their HP until they ran into water.
*Warp Ring - Warped you to predetermined areas on the map.
300 Club Card - Achieved by bowling a perfect 300. Allowed access to a special bowling alley.
Angel - GC Prize, did nothing but show you as an angel.
Astral Projection - GC Prize, showed a projection of your character. I forget whether you could walk around as a projection.
Betting System - It didn't work during my time afaik.
Birdshot - Attached Bruges Bird to hook/chain thingies. Effectively a hookshot.
Bomb Stock - I forget.
Call Spaceship - Like the Warp Ring, but would bring you to specific locations and Lunaris.
Cane of Brugara - Used magic. Was like the bow with nukeshot except used the jolt bomb animation and could freeze players.
Cape of the Hero - I forget.
Cheese - Food item.
Cheese Burger - Food Item.
Clairvoyance - GC Prize
Coin - GC Prize - Flipped coin heads/tails
Conch Shell - Did some stuff specifically quest related but not much else.
Dancing Shoes - Caused your character to dance.
Dark Knife - GC Prize - I forget
Defensive Fire - Surrounded the player in bomb explosions. May have decreased bomb inventory or used magic.
Dice - GC Prize - Rolled dice. I created this. I hear it's back.
Doll - I forget.
Entertainer - GC Prize - Different entertaining ganis
Fake Dagger - GC Prize - Caused your char to appear dead although they didn't die.
FAQ Uniform - I forget.
Fishing Rod - Caught fish, caught fighting fish. There may have been different levels.
GC Trophy - GC Prize - I forget.
Graal Radio - Didn't work when I played.
Grog - I forget.
Hamburger - Food Item
Herb - Food Item
Ice Cream - Food Item
Jellybeans - GC Prize - Gani changer
Jump Rope - GC Prize - Gani changer
Jumping Boots - GC Prize? - I forget
Knife of Judgement - Basically like the boomerang. I believe there were two levels, one which travelled further and attracted itself to enemies.
Leapfrog - Warped you over other players.
Lode Glove - Quest item, could attract certain types of stones. May have had multiple levels.
Magic Smoke - I forget.
Magic Vial - Healing item?
Meditation - GC Prize, Gani changer, may have healed the player
MiniGameSystem - Atari-like Minigames
Morpher - Copied another player's clothes/body/head/etc.
Music Maker - I forget
Noise Maker - I forget
Official Nimda Dragon's Map - Map for where to go in the Nimda Quest.
Old Graal Warper - Warped players to the Old Graal quest.
Onion - Food Item
Opposite Boots - Walk backwards. Was glitched until post-wipe.
Panda Beer - Food Item
Panda Wine - Food Item
PermaClothes TM - Stored clothes, equivalent to character slots.
Pestilence Staff - Caused players to catch disease or something.
Pizza - Food Item
Poly Trail - GC Prize - left a trail of polygons behind a player while they walked.
Portable Chair - GC Prize - sit anywhere
Quiver - Separate from *Quiver. Bow refill
Salami - Food Item.
Skull Storm - GC Item. Made crazy gani.
Skull Summon - GC Item. Made crazy gani.
Soft Drink - Food Item
Space Storm - GC Item. Made crazy gani.
Space Toy - GC Item. RC spaceship.
STARCON FireMine - Bombs with detonaters. Ugly graphic though.
Stone Morph - GC Item. Made you look like a stone.
Sub - Food Item.
Suicide Dagger - GC Item, actually kill yourself.
Sword Dance - GC Item, fancy gani.
Tomato - Food Item.
Treasure Map - Quest where you dug yourself into a cave to get different items.
Trident - Longer range than sword, could pick up bushes for additional damage. Longer move delay than sword.
TriSword - GC Item - I forget
War Staff - Like pestilence staff, but did something else.
Zorbi Ring - Let you dive into underwater levels.