To modify the first card in a booster pack (actually it just adds an extra card, you still get the rares;) use 01XX00C4 This works like the pokemon codes for red blue and yellow. Replace the XX's with the code for any card. The codes go in the same order as the card list in the deck building menu, starting with energy.

Pokémon TCG Gameboy - Gameshark Codes

PoJo Note: We've got a HUGE update for you guys and gals!! As always keep the codes and tips coming.
Have Fun! Aaron

Here's the codes for all Promo cards (including the legendary cards) as the
11th card on every pack:

• #P01 Pokemon League Edition Arcanine => 013700C4
  #P02 Legendary Moltres => 014000C4
  #P03 Legendary Articuno => 015F00C4
  #P04 Ivy Pikachu => 016200C4
  #P05 Jumping Pikachu => 016300C4
  #P06 Flying Pikachu => 016400C4
  #P07 Surfing Pikachu => 016500C4
  #P08 Mt. Fuji Surfing Pikachu => 016600C4
  #P09 Movie Electabuzz => 017000C4
  #P10 Legendary Zapdos => 017600C4
  #P11 Slowpoke => 019100C4
  #P12 Movie Mewtwo => 019E00C4
  #P13 Video Mewtwo => 019F00C4
  #P14 Lilypad Mew => 01A000C4
  #P15 Pokemon 1st Movie CD Jigglypuff => 01AD00C4
  #P16 Legendary Dragonite => 013700C4
  #P17 Trainer: Imakuni? => 01C800C4
  #P18 Trainer: Super Energy Retrieval => 01CE00C4
  #PXX Card Pop: Pokemon TCG Guide Venusuar
  #PXX Card pop: Illusion Mew

I hacked a code that modifies the first card in a booster pack. So, whenever you receive a booster pack, the top card will be the one designated. You can even use this for the Phantom Cards (03 and A1):

• The code is: 01??00C4
  Also, for infinite boosterpacks in the mail, enter these codes:
  01811ED1
  01851FD1
  018420D1
  018221D1

Get infinate any booster pack in PC:

• 01811ED1 colosseum
  01851FD1 evolution
  018420D1 mystery
  018221D1 laboratory
  Choose cards in booster pack:
  01??00C4 first slot
  01??01C4 second slot
  01??02C4 third slot
  01??03C4 fourth slot
  01??04C4 fifth slot
  01??05C4 sixth slot
  01??06C4 seventh slot
  01??07C4 eighth slot
  01??08C4 ninth slot
  01??09C4 tenth slot

Gb Pokemon Trading Card Game 2 Cheats Always Headset

If you don't like to battle, and want to win easily, use this code:

• 0100C8C3
  This code makes your opponent's active Pokemon faint if you attack them or
  they attack you. =)

Gb Pokemon Trading Card Game 2 Cheats Always Headsets

I have another gameshark code for TCG catridge.

• Modify 1st card in a booster pack:
  00xx01C4
  Substitute the xx for #'s like you did for the code to
  add a card.
  

Alright, here's a nice little cheat for ye. =)

• For infinite booster packs in the mail, use the codes:
  01811ED1
  01851FD1
  018420D1
  018221D1
  To modify the first card in a booster pack (actually it just adds an
  extra card, you still get the rares ;) use
  01XX00C4
  This works like the pokemon codes for red blue and yellow. Replace the
  XX's with the code for any card. The codes go in the same order as the
  card list in the deck building menu, starting with energy.
  Code list:
  01 Grass Energy
  02 Fire Energy
  03 Water Energy
  04 Lightning Energy
  05 Fighting Energy
  06 Psycic Energy
  07 Double Colorless Energy
  08 Bulbasaur
  09 Ivysaur
  0A Card Pop Venusaur
  0B Venusaur
  0C Caterpie...
  It continues in the same pattern, I'm not sure how far it goes. For a
  Card Pop Mew, use A1 as the modifier digits. -Te'nala

Here is the list that Te'nala didn't include when using his booster pack
modification code.

• 01 Grass Energy
  02 Fire Energy
  03 Water Energy
  04 Lightning Energy
  05 Fighting Energy
  06 Psychic Energy
  07 Double Colorless Energy
  08 Bulbasaur L13
  09 Ivysaur L20
  0A GB Venusaur L64
  0B Venusaur L67
  0C Caterpie L13
  0D Metapod L21
  0E Butterfree L28
  0F Weedle L12
  10 Kakuna L23
  11 Beedrill L32
  12 Ekans L10
  13 Arbok L27
  14 Nidoran(F) L13
  15 Nidorina L24
  16 Nidoqueen L43
  17 Nidoran(M) L20
  18 Nidorino L25
  19 Nidoking L48
  1A Zubat L10
  1B Golbat L29
  1C Oddish L8
  1D Gloom L22
  1E Vileplume L35
  1F Paras L8
  20 Parasect L28
  21 Venonat L12
  22 Venomoth L28
  23 Bellsprout L11
  24 Weepinbell L20
  25 Victreebel L42
  26 Grimer L17
  27 Muk L34
  28 Exeggcute L14
  29 Exeggutor L35
  2A Koffing L13
  2B Weezing L27
  2C Tangela L8
  2D GB Tangela L12
  2E Scyther L25
  2F Pinsir L24
  30 Charmander L10
  31 Charmeleon L32
  32 Charizard L76
  33 Vulpix L11
  34 Ninetales L32
  35 GB Ninetales L35
  36 Growlithe L10
  37 Arcanine L34
  38 GB Arcanine L45
  39 Ponyta L10
  3A Rapidash L33
  3B Magmar L24
  3C Magmar L31
  3D GB Flareon L22
  3E Flareon L28
  3F Moltres L35
  40 GB Moltres L37
  41 Squirtle L8
  42 Wartortle L22
  43 Blastoise L52
  44 Psyduck L15
  45 Golduck L27
  46 Poliwag L13
  47 Poliwhirl L28
  48 Poliwrath L48
  49 Tentacool L10
  4A Tentacruel L21
  4B Seel L12
  4C Dewgong L42
  4D Shellder L8
  4E Cloyster L25
  4F Krabby L20
  50 Kingler L27
  51 Horsea L19
  52 Seadra L23
  53 Goldeen L12
  54 Seaking L28
  55 Staryu L15
  56 Starmie L28
  57 Magikarp L8
  58 Gyarados L41
  59 Lapras L31
  5A Vaporeon L29
  5B Vaporeon L42
  5C Omanyte L19
  5D Omastar L32
  5E Articuno L35
  5F GB Articuno L37
  60 Pikachu L12
  61 Pikachu L14
  62 Pikachu L16
  63 Pikachu L16
  (No. This is not a double print. This one is jumping through the air.)
  64 Flying Pikachu L12
  65 Surfing Pikachu L13
  66 Surfing Pikachu L13
  (Yes. This looks like the same card to me.)
  67 Raichu L40
  68 Raichu L45
  69 Magnemite L13
  6A GB Magnemite L15
  6B Magneton L28
  6C Magneton L35
  6D Voltorb L10
  6E GB Electrode L35
  6F Electrode L42
  70 Electabuzz L20
  71 Electabuzz L35
  72 GB Jolteon L22
  73 Jolteon L29
  74 Zapdos L40
  75 Zapdos L64
  76 GB Zapdos L68
  77 Sandshrew L12
  78 Sandslash L33
  79 Diglett L8
  7A Dugtrio L36
  7B Mankey L7
  7C Primeape L35
  7D Machop L20
  7E Machoke L40
  7F Machamp L67
  80 Geodude L16
  81 Graveller L29
  82 Golem L36
  83 Onix L12
  84 Cubone L13
  85 Marowak L26
  86 GB Marowak L32
  87 Hitmonlee L30
  88 Hitmonchan L33
  89 Rhyhorn L18
  8A Rhydon L48
  8B Kabuto L9
  8C Kabutops L30
  8D Aerodactyl L28
  8E Abra L10
  8F Kadabra L38
  90 Alakazam L42
  91 Slowpoke L9
  92 Slowpoke L18
  93 Slowbro L26
  94 Gastly L8
  95 Gastly L17
  96 Haunter L17
  97 Haunter L22
  98 Gengar L38
  99 Drowzee L12
  9A Hypno L36
  9B Mr. Mime L28
  9C Jynx L23
  9D Mewtwo L53
  9E Mewtwo L60
  9F Mewtwo L60
  (Again, it looks like a double, but the latter has a fiery aura around it.)
  A0 Mew L8
  A1 GB Mew L15
  A2 Mew L23
  A3 Pidgey L8
  A4 Pidgeotto L36
  A5 GB Pidgeot L38
  A6 Pidgeot L40
  A7 Rattata L9
  A8 Raticate L41
  A9 Spearow L13
  AA Fearow L27
  AB Clefairy L14
  AC Clefable L34
  AD Jigglypuff L12
  AE GB Jigglypuff L13
  AF Jigglypuff L14
  B0 Wigglytuff L36
  B1 GB Meowth L14
  B2 Meowth L15
  B3 Persian L25
  B4 Farfetche'd L20
  B5 Doduo L10
  B6 Dodrio L28
  B7 Lickitung L26
  B8 Chansey L55
  B9 Kangaskhan L40
  BA Tauros L32
  BB GB Ditto L19
  BC Eevee L12
  BD Porygon L12
  BE Snorlax L20
  BF Dratini L10
  C0 Dragonair L33
  C1 GB Dragonite L41
  C2 Dragonite L45
  C3 Professor Oak
  C4 Imposter Professor Oak
  C5 Bill
  C6 Mr. Fuji
  C7 Lass
  C8 Imakuni?
  C9 Pokemon Trader
  CA Pokemon Breeder
  CB Clefairy Doll
  CC Mysterious Fossil
  CD Energy Retrieval
  CE Super Enerergy Retrieval
  CF Energy Search
  D0 Energy Removal
  D1 Super Energy Removal
  D2 Switch
  D3 Pokemon Center
  D4 Poke Ball
  D5 Scoop Up
  D6 Computer Search
  D7 Pokedex
  D8 PlusPower
  D9 Defender
  DA Item Finder
  DB Gust of Wind
  DC Devolution Spray
  DD Potion
  DE Super Potion
  DF Full Heal
  E0 Revive
  E1 Maintenance
  E2 Pokemon Flute
  E3 Gambler
  E4 Recycle
  Hope this helps you win your battles. My suggestion is to go to the Prof's
  Lab with Te'nala's Infinte Boosters Codes, and then go to the computer and
  keep reading the mail that is there until you get as many of the card that
  you are looking for that you want.
  --Whisper31