Salazzle

Salazzle is the only Pokemon to feature a Fire and Poison typing (other than its pre-evolution). Its ATK stat is respectable, with a passable moveset to support it. Unfortunately Salazzle is extremely frail and requires dodging to sustain itself in raids. Other Pokemon like Reshiram, Darumaka, or Roserade make for better PvE attackers, and thus Salazzle can be considered a Dex entry if stronger Pokemon are available. Don't bother for gym defense, one Earthquake will very likely KO it. 

Best PvE Offensive Moveset

• Poison Jab pairs well with Sludge Wave to fulfill a Poison-type role.
• Incinerate pairs well with Fire Blast to fulfill a Fire-type role. 
• Poison Fang is meant for PvP. 
• Dragon Pulse lacks STAB and is considered a subpar move. 

Best PvE Defensive Moveset

• Incinerate is the most powerful Fast Move in the game for defense, with a huge 29 base power. 
• Poison Jab is a joke by comparison. 
• Poison Fang is a very weak Charge Move, but can be spammed frequently as a 3-bar move. 
• Dragon Pulse is more likely to be used as a 2-bar move, and hits quite hard. 
• Sludge Wave might be too slow to access before Salazzle faints. 
• Fire Blast is even slower and should not be used for defense. 

Both Fast Moves sport above average damage output and energy generation, with different typing coverage. Either are viable, though Incinerate has a very long animation that makes it more difficult to play. 

Poison Fang is mandatory due to its low energy cost, enabling Salazzle to bait shields, as well as applying a debuff utility. Sludge Wave and Fire Blast are powerful STAB Charge Moves that demand a lot of energy to use. It is recommended to choose a different typing of the Fast Move in order to provide coverage. Dragon Pulse lacks STAB and is considered a subpar move, but can still be useful for its slightly lesser energy cost and neutral damage.