Here's a big ol' list of most of the item IDs currently in the mod! Some have been left out due to spoilers.

Anything that has a [] beside it means that the keyword inside can be replaced by any on the given list, of course, without the brackets when used with the /spawnitem command.

+Tiles

• Blocks
  
  • blueslime
    
  • gyrbarrier
    
  • jyinkubrick
    
  • jyinsoilmaterial
    
  • jyinstonematerial
    
  • ouronpanel
    
  • ouronpaneldark
    
  • synthpanel
    
  • rawauromero
    
  • [direction]auromero[color]
    > direction: none, ver, hor
    > color: black, classic, natural, white
    
  • voidumblock[color]
    > color: none, blue, decay, green, natural, orange, pure, purple, red, yellow
• Platforms
  
  • [color]auromeroplatform
    > color: black, classic, natural, white
    
  • energyplatform
    
  • ouronplatform
    
  • ouronplatformdark

+Armor

• GSF
  
  • gyrstarter[slot]
    > slot: helm, chest, legplating
    
  • gyr[metal][slot]
    > metal: iron, steel, titanium, dura
    > slot: helm, chest, legplating
• Seal
  
  • gyr[element][tier][slot]
    > element: earth, elec fire, water, wind
    > tier: 1(T5), 2(T6)
    > slot: helm, chest, pants
• Others
  
  • jyinku[slot]
    > slot: helm, chest, pants
    
  • radiant[slot]
    > slot: helm, chest, pants
    
  • voidum[slot]
    > slot: helm, chest, plating
    
  • stablevoidum[slot]
    > slot: helm, chest, plating
• Cosmetics
  
  • gyrblank[slot]
    > slot: helm, chest, pants
    
  • gyrlongchest
    
  • gyrsleeveless
    
  • gyrflower
    
  • gyrheadset
    
  • gyrshades
    
  • gyrsocks
    
  • gyrbaggypants
    
  • hexingtear_[slot]
    > slot: head, chest, pants

+Backitems

• Hexorb
  
  • [module]hexorb
    > module: air, energy, health, glow, jump, run, agility, power, survival, elite
• Cosmetics
  
  • nulloidback
    
  • obeliskback
    
  • sunback

+Weapons (NOTE: This list has been subject to rework! This list may be outdated in the future.)

• GSF
  
  • gyrstarterbroadsword
    
  • startergsfpistol
    
  • gyr[tier][item][module]
    > tier: tier1, tier2, tier3, tier4, tier5, tier6
    > item: dagger, shortsword, shield, hammer
    > module: none, *fire, *shock, *poison, *slow (*only available with tier6)
    
  • gsfpistol
    
  • gsfassault
    
  • gsfsnipe
    
  • gsfcannon
    
  • gsf[item][tier]
    > item: pistol, buster, assault,beam, snipe, bow, cannon, shotgun, cluster
    > tier: tier5, tier6, tier7, tier8, tier9, tier10
    
  • gyr[tier]minirocket
    > tier: tier1, tier2, tier3, tier4, tier5, tier6
    
  • gsfbackup1
    
  • gsfbackup2
• Seal
  
  • gyr[tier/element][item]
    > tier: tier1, tier2, tier3, tier4, element1, element2
    > element: earth, elec, fire, water, wind
    > item: chakram, broadsword, scythe, spear
• Others
  
  • jyinku[weapon]
    > weapon: javelin, knife, staff
    
  • gyrusenreaper
    
  • hexingtiershield[inert]
    
  • hexingtearsword[inert]
    
  • infsword[fake]
    
  • konuesword[broken]
    
  • goldbuster
    
  • radiantbow
    
  • seethinglance
    
  • voidum[weapon]
    > weapon: broadsword, spear, chakram
    
  • zeqwahring

+Tools

• GSF
  
  • gsfdrill[tier][modifier]
    > tier: 1, 2, 3
    > modifier: none, b
    
  • laserhook
• Misc
  
  • hoverbikecontrollerouron
    
  • sleekhoverbikecontrollerouron

+Crafting Mats

• Unlocks
  
  • gyrarmors
    
  • gyrcraftingstations
    
  • gyrfoods
    
  • gyrfurnitures
    
  • gyrhexorbs-modules
    
  • gyrmetals-tools-blocks
    
  • gyrweapons-melee
    
  • gyrweapons-range
• Metals
  
  • crushedcopper
    
  • crushediron
    
  • kaisureBar
    
  • metalmix
    
  • ouronbar
    
  • ourongoop
    
  • voidumbar
    
  • voidumore
    
  • whitecoal
• Modules
  
  • [type]chip
    > type: air, energy, glow, health, jump, run, mixer, elite, fire, poison, shock, slow, breaker
• Codices
  
  • [element]CodexInert
    > element: earth, elec, fire, water, wind
• Seals
  
  • [element]seal
    > element: blank, earth, elec, fire, water, wind
• Others
  
  • jyinku[drop]
    > drop: blood, coordinates, emperortrophy, eye, heart, hide, trophy1, trophy2
    
  • emptyhexorb
    
  • scarletCore
    
  • skyCore
    
  • sleepyCore
    
  • voidumCore
    
  • gyrportalscraps
    
  • konuemouth
    
  • ouronswordfragments
    
  • radiantcrystal
    
  • stabilityorb
    
  • blueTaizune
    
  • redTaizune
    
  • ouron1
    
  • ouron10
    
  • ouron100
    
  • ouron100

+Food (NOTE: This list has been subject to rework! This list may be outdated in the future.)

• Produce
  
  • gyrfruit[produce]
    > produce: pooik, vaelo, shuk, rounp
• Entrees
  
  • horushim
    
  • rounplum
    
  • viatshu

+Objects (NOTE: This list has been subject to rework! This list may be outdated in the future.)

• Portals
  
  • dimLink[variant]
    > variant: Scarlet, Sky, Sleepy, Voidum
    
  • gyrpocketportal[variant]
    > variant: none, return, Scarlet, Sky, Sleepy, Voidum
    
  • gyrportal
    
  • gyrmachine
• Crafting Table
  
  • gsfdatabank
    
  • gyraltar
    
  • gyrcookingtable
    
  • gyroven
    
  • gyrusenicanvil
    
  • gyrusenictable
    
  • hexorbmodulestation
    
  • hexorbstation
    
  • voidumamalgamator
• Farmables
  
  • gyrfruit1
    
  • gyrfruit2
    
  • gyrveg1
    
  • gyrveg2
• Chests
  
  • gyrchest
    
  • gsfchest
    
  • darkgsfchest
    
  • gyrbookcase
    
  • gyrfridge
    
  • [color]auromerobookcase
    > color: black, classic, natural, white
• Furniture
  
  • flaggyrusen
    
  • gyr[furniture]
    > furniture: bed, chair, block, energydoor, light, table
    
  • [color]auromero[furniture]
    > color: black, classic, natural,white
    > furniture: banner, bed, bookcase, chair, door, light, table
    
  • [element]sealbanner
    > element: earth, elec, fire, water, wind
    
  • gyrbones
    
  • [vertical]ourondoor
    
  • [vertical]ourondoordark
    
  • ouronteleporter
    
  • [size][color][direction]entrance
    > size: small, large
    > color: red, blue
    > direction: left, right
    
  • gyrfountain
    
  • gyrbeachchair
    
  • gyrcubator[color]
    > color: blue, gray, green, purple, red, skyblue, turquoise, yellow
    
  • gnumber[number]
    > number: 0 through 9
    
  • astrogyr
    
  • gyrpic
    
  • gyrtaro
    
  • robogyr
    
  • roboren
    
  • gyrplush[variant]
    > variant: bee, black, blue, cyan, darkgreen, egg1, egg2, green, magenta, orange, punk, purple, red, special, white, yellow
    
  • gyrseatleft
    
  • gyrseatright
    
  • gyrstreetlamp