Reshiram

Reshiram was the first of the Tao Trio to arrive in Pokemon Go, and has always been a fan favorite partly due to it being a mascot of the Pokemon Black game. With a very high ATK stat, very solid stats overall, and a powerful moveset, Reshiram is massively powerful, and is an outstanding option for sheer Fire Type damage output should your team be lacking.

If you seek Truth, then Reshiram is the Pokemon for you.

Best PvE Offensive Moveset

• Fire Fang is Reshiram's strongest fast move, and pairs well with Fusion Flare or Overheat to fulfill a Fire-type role.
• Fusion Flare* is Reshiram's signature move, available starting from January 1, 2023. Its strong parameters makes Reshiram almost unmatched as a Fire attacker.
• Overheat is worse, but is still a viable choice.
• Dragon Breath isn't too far behind in performance, and can pair with Draco Meteor to fulfill a Dragon-type role if needed. 
• Stone Edge sports the fastest damage window and is quite powerful, but lacks STAB. 
• Crunch can be used more frequently, but has the worst damage output without STAB. 

Dragon Breath is preferred for its powerful STAB damage output and average energy generation. Fire Fang is inferior stat-wise, but also benefits from STAB, and is more threatening against Steel-types.

Fusion Flare* boasts incredible DPE and is also one of Reshiram's cheapest Charged Attacks, making it a staple move. It offers Reshiram a baseline consistency in utilizing its incredible STAB combination, and thanks to that, its secondary Charged Attack options are open:

• Draco Meteor offers Reshiram the most potential, ensuring that a farmed Reshiram will threaten everything in the game, but its cost and self-debuff may make it difficult to utilize in 1v1 matchups.
• Overheat's raw power makes it a viable secondary move to burst down certain targets that Fusion Flare may be insufficient against, such as Dialga or Zacian, but it lacks coverage and forces Reshiram to rely heavily on Dragon Breath for it.
• Stone Edge is a good move overall and offers some coverage without the risk of debuffing, but lacks the potency of its other moves. It can be used to break apart Ho-Oh and Togekiss, and it can dent Kyogre.
• Crunch used to be a staple move due to its low cost, but is no longer necessary due to Fusion Flare taking that role. It still can be used as a cheap attack to pressure Giratina with, and can also potentially drop Defense to further bolster Reshiram's powerful Fast Attack pressure.