What types would best complete my team in Let's Go! Eevee?

Question

Keep:
Charizard / Blastoise / Venusaur / Eevee
Replace:
Nidoking / Pikachu

Maybe a Ground/Rock? Flying? Dragon?
No Pokemon that require trading, please, I have no friends that like Pokemon lol

Comments

In the original Yellow, the best Pokemon were Nidoking, Clefable, and Kadabra. However, game mechanics have changed a bit since then.

---

If you want Faster Pokemon, Kadabra/Alakazam, Electrode, Aerodactyl, and Dugtrio are great options. If you want bulkier Pokemon, Clefable, Nidoking, Snorlax, and Lapras are great options.

---

How far are in the game? Our answer will also depend on that.

---

Not a full answer, but https://www.smogon.com/forums/threads/wip-lets-go-in-game-tierlist.3644062/

Answer 1

Here is what your current 4 Pokémon kept can cover based on type.

Fire/Flying -> Grass2, Ice, Fighting, Bug2, Steel
Water -> Fire, Ground, Rock
Grass/Poison -> Water, Grass, Ground, Rock, Fairy
Normal -> _

Total Types covered:
Fire, Water, Grass3, Ice, Fighting, Ground2, Bug, Rock2, Steel, Fairy

Total Types left uncovered:
Normal, Electric, Poison, Flying, Psychic, Ghost, Dragon, Dark
__
Since you said "No trading", here are some options:

Fighting and Ground/Rock

Fighting -> Normal, Ice, Rock, Dark, Steel []
Ground/Rock -> Fire2, Electric, Ice, Poison, Flying, Bug, Rock, Steel [[]]

Total Types covered:
[Normal], Fire3, Water, [[Electric]], Grass3, Ice2, Fighting, [[Poison]], Ground2, [[Flying]], Bug2, Rock3, [Dark], Steel2, Fairy

Total Types left uncovered:
Psychic, Ghost, Dragon
__
Now for the Pokémon:

For the Fighting-type: Mankey or Primeape, Poliwrath, Machop or Machoke or (Machamp *exclude*), Hitmonlee, and Hitmonchan

For the Ground/Rock-type: Geodude or Graveler or (Golem *exclude*), Onix, and Rhyhorn or Rhydon

Comments

I'd suggest replacing Eevee with Haunter (you don't need to evolve it into Gengar), that way you can cover Psychic and Ghost. So, the only type left uncovered for would be Dragon.

---

Since you're excluding Machamp and Golem, why don't you include Machoke and Graveler? There's no rule saying that all Pokemon need to be fully evolved.
Also, Eevee can cover just about every type except normal, electric, dark, and fairy.