Okay, since there are a lot of like... evil duds, I'm only doing the main characters... and really cool evil dudes! I'm sorry, but the first seven volumes of the manga, those evil dudes... I just don't like 'em ):
Main Characters
~ Motou Yuugi
~ Yami no Yuugi
~ Jounouchi Katsuya
~ Honda Hiotru
~ Mazaki Anzu
~ Ryou Bakura
~ Otogi Ryuuji
~ Ishtar Isis
~ Jounouchi Shizuka
~ Kujyaku Mai
People who are "All in how you look at them"
~ Kaiba Seto
~ Kaiba Mokuba
~ Kaiba Noa
~ Shadi
~ Marik
Evil Characters
~ Yami no Bakura
~ Yami no Marik
~ Zork
Ancient Egypt
~ Pharaoh Atemu
~ Priest Mahaado
~ Priest Seto/Seth
~ Priest Akunadin
~ Priest Isis
~ Priest Karim
~ Priest Shadi
~ Mana
~ Kisara
~ Theif King Bakura
~ Shimon Muran
~ Pharaoh Akunumakan