OPItems

Utility
Experience Storage - Stores XP
Portable Ender Chest - A portable ender chest
Item Frame Hider - Makes item-frames invisible
Super Sponge – Clears large water areas
Lava Sponge – Clears lava in a medium radius
Night Visor – Grants permanent night vision when equipped
Water Helmet – Allows infinite underwater breathing
Skull Imitator – A fake skull with your appearance
Speed Leggings – Grants extra speed
Eternal Steak - An eternal steak
Crafter – Opens a crafting table
Portable Work Station - A workstation for everywhere
Infinite Milk Bucket - When in need of milk
Infinite Rocket - A Rocket built for flying even further

Protection & Anti-Grief Tools
Anti Explosion Helmet – Greatly reduces explosion damage
Anti Fall – Prevents fall and collision damage while in inventory
Protective Elytra – Elytra with extra protection
Defuser – Safely disarms landmines

Explosives & Chaos Tools
TNT-Detonator – Detonate selected TNT blocks remotely
TNT Bow – Spawns multiple primed TNTs on impact
Wand of Boom – Triggers small explosions
Wand of Massive Boom – Triggers larger explosions
Boomer – Shoots TNT
Landmine – Explodes on contact
Blitzer – Strikes lightning on targeted block

Combat & PvP Gear
Cursed Sword – Instantly kills enemies (not players), teleports user (might come with unforseen effects)
Endsword – Teleports you 8 blocks in your current direction
Wand of Blocks – High damage, but with risk of backfire
The Blocky Sword – Deals great base damage
Knocky the Stick – Knockback X
Blazer – Shoots fireballs
Bower – Fires arrows without consuming any
The Anti Damage – Protection 75 armor
Wand of Warden – Summons a Warden (at the cost of some health)
Wand of Invisibility – Grants invisibility
Piercer – A bow that shoots throught entities

Mobility & Travel
Fly Feather – Grants creative-style flight
Laucher – Launches you upward
Hook of Velocity – Enables fast directional movement
Enderpearler – Throws an Ender Pearl in view direction
Wand of Home – Teleport to your saved location
Endsword – Short-range directional teleport
Portal2Go – Access the Nether from anywhere
Private Pocket Dimension Wand – Teleports you to your own private dimension
Subspace Dimension Wand - A subdimension for faster travel
Miscellaneous

Pig Cannon – Fires pigs
Pig Spawn Egg – Used for crafting only
Fire Shoes – Cosmetic fire trail
Strange Bottle - A strange Bottle with strange liquid with strange effects

Commands:

/opitems < report | upgradeItems | give | help | recipes | gui | update | remove_recipes | skull | version | um | config>
/items <remove | player_heap | remove_now>

Debug Commands:
/opitems <super_sponge | reset_cursed_sword_list | display_sword_list | cancel_automated_item_removal | reset_landmines>

OPItems can be controlled externally/automatically via an API.

How2API

All methods are properly described if the javadoc is used.