If you defeat everyone untill Kaiba 20 times you get Gemini elf booster pack, Blue-Eyes White Dragon booster pack, Exodia booster pack, Launcher Spider booster pack, Battle Ox booster pack, Blue-Eyes Toon Dragon booster pack and Millenium Eye (sort of) booster pack.

PS: The Tribute to the Doomed trick will only work if you have the card in your hand, not on the field.