The best counters to beat Heatran raids
Heatran is the incredibly rare Fire / Steel type, the only one of its kind in all Pokémon. While this can cause people to worry about how to shoot him down for not having this guy often, there are still some good strategies to work with. Before you jump into the right counters, it's a good idea to take a look at any potential moves Heatran might have to reuse you.
Heatran can have two Fast Moves, either the Fire-type Fire Spin or the Bug-type Bug Bite. Charged attacks on the other side can be more brutal, which include two Fire type moves in the Flamethrower and Fire Blast, Rock Stone Edge type move and Iron Head steel type.
Being a Fire / Steel type Pokémon, that means it has types that are not recommended. Normally, Fire itself would be great against Steel, but the Fire typing makes that not possible here. To have your best success, you're going to want to choose one of the Ground, Water, or Combat type moves.
As a result, some of the more powerful Pokémon that you can use here are: Groudon, Grolem, Rhinastoc, Mackogneur, Kyogre and Laggron. Depending on the Pokemon, you'll want to have moves like Mud Shot or Mud-Slap on as many as possible for the Fast Move, then shuffle moves like Earthquake over as many times as you can, as well as something like Hydro Pump for the Kyogre water type. Maybe one of your best bets would be Laggron as he's a Water / Ground type and can go hard with Mud Shot and Earthquake as the best moveset.
In general, Ground and Fighting will be the main moves you want to use, with Water being the third runner-up against Heatran. You're probably going to need a bunch of people to get Heatran, although that is technically possible with two people who are very high level and have the correct matches. If you're trying to get Heatran, you're going to have some time, as it will run until February 4th.