Manga
Manga is Japanese for graphics novel, comics. We use the term manga instead of comics for their Japanese counterpart because of the noticeable difference.

Duel Disk
Duel Disk is a system developed by Kaiba Corps. Initially as a means of defeating Pegasus, however, Kaiba plan failed. Nevertheless a portable 3D holographic system is extremely useful. Later, Kaiba re-designed it so that its user would not have to "throw" the disk, instead, the user only has to place the cards into the slots, and the hologram would show up immediately. This is known as Duel Disk II and is required equipment of the Battle City tournament.

Millennium Puzzle
The Millennium Puzzle is owned by Yugi Mutou, it's uses are that it will
give the owner another personality to be smart, daring and the ability to
win in games. The person who loses will get punished. The soul of an ancient
Egyptian Pharaoh, who sacrificed his life to seal dark powers, is sealed
also in the Millennium Puzzle.

Millennium Ring
The Millennium Ring is owned by Ryou Bakura, one of Yugi's main enemy's(in a
period of time now a friend). The use of the Millennium Ring is to give the
owner a second personality of evilness. It's power given to the owner:
detecting other Millennium Items and also gaining their powers as well. It
can also seal part, or entire souls within objects. Sealed inside the
Millennium Ring is the soul of a Tomb-robber.

Millennium Anhk
The Millennium Anhk is owned by Shaadii, an Egyptian warrior who punishes
people who raid any Egyptian Tombs and Temples. The uses of that item can
see through a person's heart to see their personality etc.

Millennium Scale
The Millennium Scale is also owned by Shaadii, the use of that item is to
judge people. If the owner asks a question, the person being asked has to
answer the question honestly otherwise the Scale punishes the person being
questioned.

Millennium Eye
The owner of The Millennium Eye is called Pegasus J. Crawford (Maximillion
Pegasus), an American who is a designer of magic and wizards card game (Duel
Monsters in real life). The ability of that item is that it can see through
a person's mind to see what they are thinking about. He was given this while
on a trip to Egypt 7 years ago when peeking at a building guarding the
"Pharaoh's Memory Slate", he only wanted to see his dead girl friend again,
and got that wish when the Eye accepted him. When he lost to Yugi, Ryou
Bakura took the Eye from him.

Millennium Tauk
The owner the The Millennium Tauk is called Isis Ishtar, the eldest daughter
of the Ishtar Family. The Ishtar Family has been guarding the Pharaoh's
Memory since ancient Egypt after an undead Pharaoh sacrificed his life to
seal Dark Powers within 7 items. The use of the Tauk item is being able to
see the future. However, the powers of other Millennium Items are capable of
altering this future. (In one chapter of the manga, Isis was dueling Kaiba,
her prediction was that Kaiba would lose, however, the Millennium Rod
prevented Kaiba from losing by showing Kaiba some flashbacks).

Millennium Rod
The owner of The Millennium Rod is called Malik Ishtar, brother of Isis and
the second child of the Ishtar Family. He claimed control of this item when
he was 11, when his Father nearly killed his faithful servant and friend -
Lisid. He has had a split personality since he was 10 when his back was
engraved with the Pharaoh's Memory. His split personality came out when
Lisid fell unconscious, he killed his Father with the Rod. The Rod is also
capable of turning into a small knife. Shaadii told him that it was all the
Pharaoh's fault, so he swore that he would use The Millennium Rod to kill
the Pharaoh, who is roaming the lands searching for his memory.