FIRE monsters are commonly associated with Pyro, Dragon, and Machine, though it is not uncommon in other Types such as Warrior or even Beast. Suprisingly, there is even an Aqua-type monster with this attribute, Fire Kraken. FIRE is diametrically opposed to WATER, but there is no direct advantage outside some of the Video Games.
FIRE Monsters tend to focus on inflicting Effect Damage on your opponent's Life Points and stacking up in ATK points when on the field together, along with the appropriate lockdown cards like "Gravity Bind" and "Level Limit - Area B" to protect the burn monsters.
Though Fire Monsters can be extremely powerful, they tend to lack support for one another. Instead of focusing on combining and drawing on their strengths as a whole, couple with the fact that there are few good Spell and Trap cards to suit them than some of the other Attributes (most notably Water), Fire Monsters can be seen as having a negative impact on the opponent. They either take out Life Points slowly, and dealing some mighty damage with their high ATK or buff themselves with effects (e.g. Raging Flame Sprite, Magna Drago etc.) , rather than helping the player directly via drawing, increasing Life Points, etc.
The Structure Deck 3: Blaze of Destruction Structure Deck emphasizes combos, and if a monster itself is on the field, it will be destroyed easily because of no other monsters to support it. Ultimate Baseball Kid needs other fire monsters to survive but DNA Transplant can be used to boost him.