Ok this may take a long time but trust me it's worth it
First get to the part were isisus talks to you and duels you beat her and you will get 30 more capasity the you have to duel kiba lose and start over I did this for 5 hours and now my level is 999 and my deck 7483
red eyes black dragon-74677422 red eyes b chick-36262024 lord of d-17985575 blue eyes white dragon-89631139 dark magician46986414 black illusion ritual-41426869 la jinn the mystical genie of the lamp-97599074 the shallow grave-43434803 soul exchange-68005187 winged dragon of ra-sorry some cards dont show passwords blade knight-39507162 black pendant-65169794 gearfried the iron knight-00423705 monster reborn-83764718 swords of revealing light-72302403 butterfly dagger-elma-69243953 deal of phantom-69122763 change of heart-04031928 gogiga gagagigo-39674352.this card is strong but i think it was made to confuse people chain destruction-01248895 sword hunter-51345461 freed the brave wanderer-16556849 girochin kowagata-84620194 sword of deep-seated-98495314 magic jammer-77414722 ogre of the black shadow-45121025 rope of life-93382620 headless knight-05434080 kojikocy01184620 battle ox-05053103 bottomless trap hole-29401950 skull red bird-10202894 summoned skull-70781052 harpies brother-30532390 great angus-11813953 spellbinding circle-18807108 relinquished-64631466
Thats all for now I'll tell you more when I get some cards.
You need to have 1 witty phantom, 3 karbonala warrior, 3 celtic guardian, 3 cocoon of evolution, 1 raigeki, 1 beckon to darkness, 1 monster reborn, 3 flash assailant,1 dark magician girl . Just put those cards to your deck and you'll be unstoppable. I know all of those cards are not enough in quantity but it's of to you on what cards you would like to put in your deck after putting those cards.
P.S. To add all of those in your deck you need to have a very high deck capacity.
After you beat Bonz for the first time, go to the center alleyway through Clock Tower Square, and you will see Espa's little bros, which you may battle. After beating the two of them along with Espa, Espa will ask you a question. Answer no and he will stay so you can duel him anytime. If you say true, you will never see him again in the game, unless you start a new file.
When you are against the ghouls, beat one ghoul at each place they infest, then, duel espa roba and after you beat him, he will tell you to go to te park, go there and do NOT duel the ghouls(unless you need domino or cards).
Then go to the bottom-left side of the park and you will see bandit keith and he will beat weevil. after that, weevil leaves and bandit keith will duel you.
After you beat him, save immediatly and go to the art museum and ishizu will be there and she will duel you, if you beat her, kaiba will duel you next. if you beat him, ishizu will give you the egyptian god card Obelisk the Tormentor!