A metal Dragon with giant wings and the ability to breathe fire.

As it draws near, you see that it is no ordinary Dragon, if any Dragon could be considered “ordinary.” It is half flesh and half iron. Even its wings are metallic, bearing a strange arsenal of weaponry unlike any you have ever seen. - Tome of Encounters (RPA-SQ1)

The Iron Dragon is outfitted with destructive armaments on its metal parts;

A metal projectile fires from its wing, creating an explosion forceful enough to bring down one of the walls of the arena. The crowd screams as members of the audience are torn apart or blown into ashes. - Tome of Encounters (RPA-SQ1)

Iron Dragons are powered by life-crystals, often installed in the nape of their necks;

…you clamber quietly up to open the back of the Dragon’s neck. You’re thrilled to discover the life-crystals still in their sockets. - Backstory Codex - Artificer (RPA-BC)