Hi I wanted to ask are there any tools that allow you to add custom cards to yugioh World championship 2011. I'm asking because I wanted to all the cards that aren't in the game till the final pack I want to add cards like shooting quasar dragon
Well even if I can't give you proofs I can say there aren’t and probably never will.
For this it would be necessary a high level hacking.
People already struggle to change sprites, translate, modify some contents etc.
Adding new cards involve all above and including the necessity of free storage space
into the rom and memory addressing.
Also more hacking would be necessary to make the AI understand and use them.
I guess you don’t just want them in an album to show.
To get something closer to what you want
It may be easier to create an homebrew or a rom hacking that won’t be the same as the original game.