Items are oftentimes obtained from treasure chests. Although at some instances, they are also rewarded by NPCs upon completing their Quests. There are items too that are only acquired by copying (with the discovery tool) and then there are also the items that can be bought from the trader. Items consist mainly of a variety of melee and ranged weapons. There are other items used to complete quests as well.
Weapon items in the game greatly increase your combat capability. As with any sandbox game, the world ain't complete without the accompaniment of player-combat feature. The variety of weapons enables players to pick either to fight with ranged or close combat weapons. Depending on the weapon too (or sometimes with how hard to obtain the item is), increase in their damage can also be observed - granting you a better fighting chance against hostile Creatures/characters.
Here is a short list of common items/weapons you'll find in the Different Worlds:
Apple - Enables the player to throw it.
Banana - Enables the player to throw it.
Bazooka - Ranged weapon with great explosive damage.
Binoculars - Special item requested by some NPCs in Quests. If picked as weapon, it acts simply as a cosmetic.
Blunderbuss - Vintage ranged gun weapon. Slow firing, and recoils.
Bow and Arrow - Starter weapon found easily during the earlier parts of the game (or bought from trader). Slow ranged weapon with minimal damage.
Camera - Special item requested by some NPCs in Quests. If picked as weapon, it can take pictures of the landscape.
Club - Melee weapon with minimal damage.
Cutlass - Melee weapon with minimal damage.
Dynamite - Enables the player to throw it.
Fish - Enables the player to throw it.
Ice Cream - Special item requested by some NPCs in Quests. If picked as weapon, it acts simply as a cosmetic.
Lamp - Earned upon reaching a certain level in the game. Helpful on dark areas like underground pockets.
Pistol - Starter weapon found easily during the earlier parts of the game (or bought from trader). Ranged weapon with minimal damage (at least stronger than the bow and arrow)
Rifle - Slow ranged weapon but with great damage.
Shield - Melee equipment, used to block attacks.
Sword - Melee weapon with great damage.
Telescope - Special item requested by some NPCs in Quests. If picked as weapon, it acts simply as a cosmetic.
Umbrella - Special item earned with a character costume set in the game. If picked as weapon, it helps you glide more subtly when skydiving for more control on your landing.