There are many kinds of Monster Cards. This game is more than a simple slugfest, so monsters with high Attack and Defense Points will not be enough. There are also monsters with strong special effects even though their ATK and DEF points are low. Therefore, your success in a Duel depends on how skillfully you can make use of the different kinds of cards.
Normal Monster Cards
These are Basic Monster Cards without special abilities. Many Normal Monsters have higher Attack Points and Defense Points than Effect Monsters, instead of having special abilities.
Effect Monster Cards
A monster that has special abilities. The effects of these monsters are split into five categories:
Fusion Monster Cards
Fusion Monsters are also placed in your Extra Deck (not in your Main Deck). They are Summoned by using the specific monsters listed on the card (called Fusion Material Monsters) combined with the Spell Card "Polymerization." They usually have special abilities and very high Attack Points as well.
Gemini Monster Cards
Treated as Normal Monsters while face-up on the field or in the Graveyard. You can Normal Summon it to have it be treated as an Effect Monster with a specific effect.
Pendulum Monster Cards
Pundulum Monster cards are a new kind of card that blurs the lines between Monsters and Spells! They can be Summoned as monsters to attack or defend, or you can activate them as Spell Cards in your Pendulum Zones to activate extra special abilities and allow you to Pendulum Summon!
Link Monster Cards
Link Monsters are monsters summoned from the Extra Deck to the Extra Monster Zone. They allow for Extra Deck monsters to be summoned to Linked Monster Zones.
Ritual Monster Cards
Ritual Monsters are special monsters that are Special Summoned with a specific Ritual Spell Card, along with a required Tribute. Ritual Monster Cards are placed in the Main Deck and cannot be Summoned unless you have all the proper cards together in your hand or on the field. Ritual Monsters generally have high ATK and DEF and some have special abilities, just like Fusion Monsters.
Spirit Monster Cards
A group of monsters that return to your hand at the end of the turn they were Normal Summoned or flipped face-up. They will not be on the field during your opponent's turn.
Synchro Monster Cards
Synchro Monsters are placed in the Extra Deck, separate from the Main Deck. You can Special Summon a powerful Synchro Monster to the field in an instant just by using the Levels of your monsters. They can be Synchro Summoned from the Extra Deck by sending 1 face-up "Tuner" monster and any number of face-up non-Tuner monsters from your side of the field to the Graveyard, when the sum of all their Levels is exactly equal to the Level of the Synchro Monster.
Toon Monster Cards
Let's make a fun Deck with Toon Monsters. They cannot attack the turn they are Summoned, but they can be Normal Summoned and some have high ATK points.
Tuner Monster Cards
In order to Synchro Summon a Synchro Monster, you need 1 Tuner (look for "Tuner" next to its Type). The Tuner Monster and other face-up monsters you use for the Synchro Summon are called Synchro Material Monsters. The sum of their Levels is the Level of Synchro Monster you can Summon.
Union Monster Cards
These monsters are a sub-grouping of Effect Monsters. They can become Equip Spell Cards for other specific monsters, giving them amazing new effects.
Xyz Monster Cards
Xyz monsters are a new and powerful kind of monster! You can summon an Xyz Monster whenever you control monsters that are the same level. Xyz Monsters start in your Extra Deck, not in your Main Deck, and wait for you to call them into action.