What is a good starting team for the whole game?

If you choose Charmander:

Charizard
Starmie
Pikachu/Raichu
Dragonite
Gengar
Marowak

If you choose Bulbasaur:

Venusaur
Raichu
Starmie
Pidgeot/Dragonite
Machamp
Rapidash

If you choose Squirtle:

Blastoise
Raichu
Victreebell
Dragonite
Rapidash
Machamp

This is an interesting questions but... A team you can assemble early in the game easily is...
Squirtle/Charmander
Caterpie
Mankey
Pikachu
Pidgey
Rattata*

*When you reach celadon city, switch your rattata/raticate for an eevee in the Pokemon mansion. If you chose charmander evolve your eevee into vaporeon. Evolve it into Flareon if you chose squirtle. If you chose charmander keep the TM misty gives you. If you chose squirtle spend some time in the game corner to get flamethrower

A very good start off team will blastoise, pikachu, nidoqueen, ninetales, pidgeot, dugtrio.
And I thank you can get better team then that and I ho

Charizard
Jolteon
Gyarados
Exeggutor
Dragonite
Rhydon

Charmander (good starter)
Magikarp (eveolves well)
Drowzee with Dream eater (important psychic)
Picachu
Mankey or geodude (ground type)
Free slot (for strength, surf, brick break...)

Venasur
Ferow
Nidoking
Primeape

I more or less bummed the game to death when it came out and all mine are quite a high level but mine were

Charizard
Dragonite
Snorlax
Exeguttor
Gyarados (Polywrath works well too)
Gengar

Not sure if this helps but that team got me through the elite 4 fairly comfortably without too much trouble.

Venusaur
Ninetails
Gyrados
Hitmonlee
Pideyot
Snorlax or pikachu

I beat the elite four with this team great power kind of hard to set up and sucks at the begging of the game but in the end it's boss.

You could use a
Jolteon
Venasaur
Lapras
Sandlash(they have good attack and defense)
Jynx
Gengar

A good Pokémon team witch I put together once was

Charizard flamethrower, earthquake, brick break, wing attack

Starmie surf, psychic, thunderbolt, icebeam

Zapdos drill peck, thunder, arielace, rain dance

Articuno icebeam, fly, detect, mist

Moltres flamethrower, steel wing, blast burn, overheat

Dragonite dragon claw, surf, flamethrower, thunderbolt

Dragonite: dragon rush tbolt icebeam aqua tail
Venasaur: petal dance earthquake solarbeam sludge bomb/toxic
Starmie: hydro pump surf tbolt psychic
Arcanine: flamethrower bite flame wheel/ retaliate/filler
Marowack: earthquake stone edge bite/filler filler
Jolteon: tbolt thunder bite double kick

If you chose charmander

Charizard
Starmie
Victreebell
Dragonite
Espeon
Primeape

If you chose Squirtle

Blastoise
Raichu
Exeggutor
Lapras/Umbreon
Flareon/Ninetales
Machamp

If you chose bulbasaur

Venusaur
Gyrados
Primeape
Gengar
Golem
Rapidash

If your starter is
Charmander: Charizard
Victreebel
Raichu/Jolteon
Dragonite
Vaporeon/Starmie/Psyduck (you may replace starmie with slowbro but I personally think starmie is better)
Pidgeot/Fearow
Squirtle: Blastoise
Victreebel
Raichu/Jolteon
Dragonite
Ninetails(LG)/Arcanine(FR)
Pidgeot/Fearow
Bulbasaur: Venasaur
Vaporeon/Starmie/Psyduck(and slowbro for starmie is also possible)
Ninetails/Arcanine
Dragonite
Raichu/Jolteon
Pidgeot/Fearow

I think what is necessary for every team should have Dragonite,Pidgeot(I think Fearow is weaker),Grass type(Poison type too),Water type(ice type/psychic type),Fire type and electric type

My Future team will be:

Blastoise
Rapidash/ Ninetails (I'm not sure)
Mr.Mime (I love it XD)
Crobat
Raichu
Victreebel

I think it's a well balanced team :P

A good team would be

Charizard-flamethrower, blast burn, heat wave, fly
Zapdos-thunder, drill peck, ancient power, thunderbolt
Dragonite-outrage, surf, wing attack, fire blast
Tyranitar-crunch, earthquake, rockslide, thrash
Gyarados-hydro pump, ice beam, surf, double edge
Crobat-wing attack, sludge bomb, shadow ball, confuse ray

This is the team I have so far. This team is really useful and strong. Best team ever in my opinion!

One fire Pokemon
One water Pokemon
One electric Pokemon
One rock/fighter Pokemon
One grass/poison Pokemon
One ghost/dark Pokemon
It doesn't matter what Pokemon you use as long you have plenty of Potions (any type) and play of healing type of medicines when you go against any trainer or when you go against the Elite Four then against you rival.

Charizard
Pidgeot
Raichu
Golduck (Trade)
Alakazam (Gengar Works Well Too)
Dragonite

My team
Charizard
Dragonite

Thats it!!!!!
I then got mewtwo after the Pokemon league and beat them again!
I was an awesome Pokemon trainer

Charizard brick break earthquake fire blast fly

Then DEEZ NUTZ HAH GOTEE

Charizard
Hitmonlee
Blastoise
Victreebel
Nidoking
Raichu

You know which moves r best
Each.

Charizard
Raichu
Lapras
Snorlax
Dragonite
Pigeot/Exeggcutor/Gengar

Bulbasaur

Pidgeot

Nidoking

Ninetales

Jolteon

Lapras

Blastoise
Raichu
Ninetails
Snorlax
Dragonite
Marowak

The best team proven for Leaf Green is:Venasaur,Jolteon,Lapras,Nidoking,Ninetails,and Dodrio. I hoped my answer has improved your gameplay!

My Team For The Main Game: (Elite Four and Gym Leaders)
Charziard
Primape
Snorlax
Jolteon
Kingler
Taurus

My Team For The 2nd match against the Elite Four:
Charziard
Primape
Snorlax
Jolteon
Crawdaunt
Sceptile

Kanto Gen 1 best team

Charmander Team:
Charizard
Vaporeon
Raichu
Nidoking
Exeggutor
Dragonite

Squirtle Team:
Blastoise
Leafeon/Exeggutor
Nidoking
Arcanine
Dragonite
Gengar

Bulbasaur Team:
Venusaur
Gyrados
Machamp
Pidgeot
Rapidash
Alakazam

Hope it helped. Although it's a late comment

Charizard
Joltean
Dragonite
Aerodactayl
Starmie
Blissey

Blastoise
Joltean
Dragonite
Arcanine
Starmie
Crobat

Venasaur
Arcanine
Joltean
Starmie
Dragonite
Blissey

Venusaur: Grass - Poison
Moves:
Solar Beam - 120
Sludge Bomb - 90
Earthquake - 100
Razor Leaf - 55

Onix: Rock - Ground
Moves:
Earthquake - 100
Iron Tail - 100
Dragon Breath - 60
Rock Throw - 50

Lapras: Water - Ice
Moves:
Surf - 95
Iron Tail - 100
Hydro Pump - 120
Ice Beam - 95 OR Thunderbolt - 90


Dragonite: Dragon - Flying
Moves:
Dive - 95
Focus Punch - 150
Fly - 70
Dragon Claw - 80

Houndoom: Dark - Fire
Moves:
Flamethrower - 95
Crunch - 80
Sludge Bomb - 90
Solarbeam - 120

Magneoton: Steel - Electric
Moves:
Thunderbolt - 95
Zap Cannon - 100
Tri Attack - 80
Spark - 65

Hands Down, without a doubt the least amount of grind, the best Team for Leaf Green is:

Start with Venusaur --
Razor Leaf, Giga Drain, Sleep Powder, & Earthquake.

After a few trainers, you'll want to pick up Nidoran. He starts with Peck, making him extremely helpful with the bug & grass types that Venusaur may have a harder time with. He will evolve into Nidorino at lvl 16, and you will get a moon stone shortly after that. Evolve him into Nidoking. This will be your HM Slave. No real need to focus on leveling him much higher. The 3rd evolution will be way overpowered early game, and will serve to help Venusaur if ever he should need it. You can teach him Dig early game to help cover more types.

NidoKing --
Strength, Cut, Rock Smash, and then a filler of choice (The standard Thrash would be fine. Earthquake would be best if you can afford. Fire Blast could be another option since we won't have any fire types in this team.
He's lower level HM slave though, so you're call.)

You will make fast & easy progress focussing on Venusaur and having Nidoking there in case. You should have Venusaur 45ish & Nidoking 30ish by the time you pick up your next three Pokemon (all about the same time.)

Snorlax --
Yawn, Rest, Body Slam, and Shadowball

Lapras --
Ice Beam, Blizzard, Hydro Pump, and Body Slam

Starmie --
Pyschic, Surf, Ice Beam, and Recover (could use Thunderbolt here if you can afford it, but not needed)

When your Venusaur and/or Snorlax is high enough level, you will going to the power plant to pick up the final piece of your puzzle. Bring plenty of great/ultra balls, and save your game right before. You're picking up Zapdos, the legendary lvl 50 bird.

Zapdos --
Drill Peck, Fly, Thunderbolt, and Steel Wing for coverage.

With no wasted XP, Zapdos starting at lvl 50, and then only "using" a 5-Pokemon team, your team will be high enough level after you finish the storyline to the Elite 4. If you do grind, I suggest you hold it out for Starmie on the Victory Road. If you have your other 4 leveled somewhere between 54-60, they will be good. Leave them be. Then you can grind Starmie up very quickly in the victory cave. High level fighting, ground, and flying Pokemon spawn... All of which are superweak to Starmie's moveset. It will be extremely fast & easy to add 5 levels to him in no time. Starmie can solo 2 of the 4 bosses at lvl 60 with ease. Zapdos will on the first boss & Gyrados of the last. Then Lapras will clean up the dragons. Venusaur is there for utility where needed... Giga Drain keeps him healed while he puts them to sleep. Earthquake is strong against certain types, and Venusaur will be much higher level than Nidoking.

Like I said, this team and strategy will make your life much, much easier in Leaf Green!