One of the hardest decisions to make in the Pokémon series is selecting a perfect team of six. With all of the different gym leaders and elite four members, it's a challenge to craft a team that handles all of the challenges ahead. Fortunately, GameFreak is usually smart enough to give the player proper options to help them progress through the game.
But what about in the original games, Pokémon Red and Blue? For all of the good they have, they are certainly still flawed. Even ignoring broken game mechanics, the game was not balanced to make things easier for the player. Which Pokémon are the best to help a new player through the game? This list will serve as a guide on what Pokémon to pick up before every gym battle. This will, however, not include starter Pokémon. Additionally, it will operate under the assumption that Pokémon stay under the highest level of the opposing gym leader.
8 Pewter City: Butterfree
For anyone familiar with Pokémon as it is now, this seems like a terrible idea. Butterfree has a quad-weakness to Rock-type moves. While that is true, for some reason Brock does not actually have any Rock-type moves on either of his Pokémon.
On top of this, neither Geodude nor Onix has a good special stat, which determines both special attack and special defense in Gen 1. For Charmander trainers struggling to bust Brock's defense, catching a Caterpie in Viridian Forest and evolving it is a solid strategy. This is only a good idea in the original games, though; Mankey is a better option in any remakes.
7 Cerulean City: Oddish/Bellsprout
Misty, the Water-type gym leader, has a strong challenge to overcome with her Starmie. Starmie is a powerful Water-type with high defensive stats, so it's imperative to bring a super-effective attack to the battle. Fortunately, the designers provided an option just north of Cerulean City.
In Pokémon Red, Oddish can be found on Route 24; alternatively, Bellsprout is the Pokémon found in Pokémon Blue. While neither has a powerhouse Grass-type move, they'll likely be evolved before fighting Misty, so their special stat can match Starmie. Pikachu is also an option, but is rarer and isn't nearly as effective as either Grass-type.
6 Vermilion City: Dugtrio
Lt. Surge, the Electric-type gym leader, has a fast and powerful Raichu on his team. With its Thunderbolt attack, it can bust through a number of unprepared trainers. Fortunately, the solution to defeating Lt. Surge can be found right outside the city. To the east of Vermilion lies the answer: Diglett's Cave, an underground path that connects Vermilion and Viridian City.
While it's not required to head down this path, in the cave, it's possible to obtain a Dugtrio. Diglett alone helps, but Dugtrio's speed and power are unrivaled this early in the game. Lt. Surge's Raichu can't even touch Dugtrio, so it's a safe bet.
5 Celadon City: Flareon
There are a few options to help take down Erika, the Grass-type gym leader. Doduo can be found on Route 16, which provides a Flying-type with a high attack. Route 8 is home to both Growlithe or Vulpix, depending on which version is being played.
However, the best solution is on that might be a bit surprising: Flareon. By going in the secret entrance behind the Celadon Mansion, the player can climb the stairs to get an Eevee as a gift. In the Celadon City Department Store, the player can purchase a Fire Stone. While evolving a Vulpix or Growlithe early limits the moves they can learn, Flareon only gets better the earlier it is evolved. As a long-term solution, Flareon is the best option for Erika and serviceable for the rest of the game.
4 Fuchsia City: Kadabra
The Poison-type gym leader, Koga, is likely going to be the gym leader challenged fifth by the player. However, it's completely up to the player whether they fight Sabrina or Koga first. Again, there are a couple of options. If the player has cleared Silph Co., they likely have picked up the Earthquake TM, which can bust Koga down with ease on any Pokémon with high attack.
However, if the player wants to completely overpower Koga's team, getting a Kadabra is the right choice. Although it can be a challenge to catch Abra and train it up, Kadabra is a fast and powerful Psychic-type. Alakazam is even stronger, but it's unlikely for someone playing Pokémon Red or Blue now to be able to trade and evolve it.
3 Saffron City: Tauros
The Psychic-type is disgustingly overpowered in the original games. It has one weakness: Bug-types. Ghost-type attacks are ineffective against Psychic in Gen 1. The best Bug-type move is Twinneedle, only learned by Beedrill. Beedrill is weak to Psychic and will get one-shot knocked out by Alakazam. Beating Alakazam requires a Pokémon that can match its speed and exploit its weak defense and low HP.
The best option at this point in the game is Tauros, found in the Safari Zone. With the Body Slam TM obtained back on the S.S. Anne, Tauros gets a powerful physical attack. Combine this with an X Speed to make Tauros faster than anything Sabrina can throw out, and it will be an easy victory.
2 Cinnabar Island: Tentacruel
Blaine, the Fire-type gym leader, can be very easily crippled by a number of Pokémon. At this point, the player has access to the Super Rod and almost every Water-type in the game. The options are limitless to take him out. The fossil Pokémon picked up in Mt. Moon can be revived here and become a strong ally, particularly Omastar.
However, it's hard to beat Tentacruel in terms of options available. Tentacool can be found surfing along Route 21, with levels wildly varying. With enough good luck, it's possible to get a level 40 Tentacool and evolve it after one level. At this point, with its high special, speed, and Surf beating anything Blaine offers, Tentacruel is a fantastic Pokémon.
1 Viridian City: Cloyster
It's easy to just say that Tentacruel can also be used to take down Giovanni, and it can. However, Ground-types have high enough attack that if they don't get one-shot, it's possible they could defeat Tentacruel. So, for trainers looking for a safer alternative, nothing is better than the Ice-type tank, Cloyster. Shellder can be obtained on a number of routes using the Super Rod, and quickly evolved using a Water Stone.
After teaching it Ice Beam using the TM found on the roof of the Celadon City Department Store, it can easily dispatch all of Giovanni's Pokémon. It might not be a clean sweep, but it'll surely be a sweep nonetheless. Just beware of Rhydon's Fissure, because one-hit-KO attacks in Gen 1 are pretty disgustingly broken.