At the top there, you see the Flare Gun, which replaces the Pyro's shotgun and lets you light up enemies at long range. In the middle? It's the Axtinguisher, the melee weapon that always makes a critical hit on flaming enemies. Finally, there's the Back Burner, which is guaranteed to crit if it hits a foe from behind.
If we still haven't cured your pyromania (we've been waiting all post to say that) check out all the details right here.