I don't know if this is all of them but it might be
PET,StudntID,TeachrID,Bucket,WatrData,Graffiti,KeyData,TagChip,HealWatr,CybBrdAx,Report,ImgData,AuthData,Umbrella,WinCardA B C D,VacData,ACDCKyDt,AreaPass,StampCrd,Rushfood,WWWID,BtlrCard,BatKey,SeaSdKey,RefrncBk,QuizBook,ScretMemo,InvteCard,SpialDat,QuizData,Coffee,ScrblDat,PngnThnk,SoulEmbl,SpinWhit,SpinYllw,SpinPink,SpinRed,SpinBlue,SpinGrn,SchPCode,WtrBannr,GrnBannr,SkyBannr,ACDCBanr
(there might be 1 more because i have 1 mission left)
There is a giant tree in the middle of Green-Area 2. Go to it and inspect it. On the back of it, hidden from your view should be a wormhole. Press A near it and Menaman will ask you if you want to jump into it. Agree. Follow the path in Undernet-Zero until you come near a tombstone / grave / monument. Inspect it. Bass will appear, though as usual. He drops a Bat Key. It unlocks a gate in Graveyard-Area. Also, at the back of Graveyard-Area is the second Bass / Forte fight. The third Bass encounter triggers when you go to Underground-Area, the place where you took a Link navi to to fight Cybeast Megaman. Step up the ramp and face two enemies: Cybeast Megaman once again and right after him, Bass. After you destroy him, he becomes a random encounter in that area.
on the way to Central Area 3, there is a piece of green road that you cannot pass through, examine it and the key is there. Use the KeyData to open the gate to Central Area 3
you need joker key
it unlocks old computer
The red key in Megaman Blue Moon can be found in the square with the four horns around it. You have to go to the left side of the map and go up the path to the warp to Undernet.
I thought that there was unlimited space for key items. How many items do you have and how many more key items do you need?
it is in the wave road of the 57th floor ;)
Key Items
http://tartarus.rpgclassics.com/mmbn4/walkthrough23a.shtml
the 3rd basement floor (or the forth) in gimialla mine
As far as I know there is no code for key items.
998 items you can hold