let's start with the monsters that are in your main deck: Normal Monsters have a yellow background; Effect Monsters have an orange background; and Ritual Monsters have a blue background.
Monsters are the most important cards in Yu-Gi-Oh, used by almost every deck to attack and defend. Around 12-18 cards in your deck should be monsters, which should support your archetype or work with your deck. Don't have too many monsters you can't summon - the majority of your dec...