Pokemon leaf green team

I need help to choose my last pokemon for the game, my team is:
Dragonite level 65( outrage,earthquake,fly and body slam)
Tyranitar level 64( earthquake, rockslide, crunch and trash)
Venausaur level 63 ( freenzy plant, solarbeam, razorleaf and sleep powder)
Starmie level 64( pshychic, surf, thunderbolt and icebeam)
Raichu( thunder, thunderbolt, slam and quick attack)

So what do you think my six and last pokemon should be?

I'm just gonna comment on the whole team cause I feel like it

Dragonite: Everythings fine, taking the advantage of STAB (Outrage + Fly). Replace Outrage with Dragon Claw if you can, power is 10 lower but it doesn't have any drawbacks (With Outrage you gotta use the same move 3 times + you got the chance to get confused after). One of the best overall stats in the game.

Tyranitar: Same with the above in my opinion, taking advantage of STAB (Crunch + Rock Slide), maybe replace Thrash with some status move (Bulk Up?). Probably best physical-damager, really high overall stats and sick attack.

Venusaur: Could replace Frenzy Plant or Razor Leaf with Sunny Day in order to get fast Solarbeams. Giga Drain/Synesthesis/Growth would be also great, anything between recovery + constant high damage (Giga Drain/Growth/Razor Leaf/Frenzy Plant for example) or sleep powder + bursting (Sunny Day/Solarbeam/Sleep Powder/Filler for example) is fine. Solarbeam kinda requires Sunny Day though (in my opinion), but Grass-type movesets are really hard to decide so I'm not gonna comment on that further. Probably best possible Grass-type.

Starmie: This is also good in my opinion, the extraordinary Water/Psychic -type makes it pretty awesome. Great advantage taken of STAB again (Psychic + Surf) and Thunderbolt for sure makes it superior against any other Water-type pokemon in 1v1. Lapras would be kinda great though, Water/Ice-type pokemon with really high overall stats, I recommend getting one.

Raichu: Thunder/Thunderbolt are fine, I would probably change Slam/Quick attack to Light Screen/Rain Dance (With Rain Dance, Thunders can't miss). Rain Dance isn't a must-have though, so saving one of Quick Attack/Slam is probably fine. Zapdos/Raikou/Jolteon would be better here though.

Your team still a Fire-type pokemon, Full-Psychic pokemon, and a real Fighting-type pokemon atleast. Here are few great pokemons that have the types you don't have at the moment:

Heracross - Bug/Fighting, high attack with really powerful Megahorn + Brick Break moves (it also has Reversal). Get Bulk-Up to make it even more powerful. Avoid Flying-types with Heracross, since Flying is 4x effective.

Arcanine/Ninetales/Moltres/Entei are all good Fire-type pokemons. Forget about Moltres/Entei if you dislike Legendary-pokemon. Moveset could be something like Flamethrower/Fire Blast/Confuse Ray or Will 'O Wisp/Sunny Day, for example.
Since you don't have the fighting-type yet, Blaziken, being a Fire/Fighting-type could be a great choice. Mixture of Fire- and Fighting-type moves + Statusmove (Like Bulk-Up) will make it pretty awesome.

One Full-Psychic could also be great. If you dislike Mewtwo, something like Alakazam with (Recover, Psychic, Calm Mind and maybe Shadow Ball/Safeguard) or Gengar with (Hypnosis, Dream Eater, Shadow Ball, Confuse Ray, Sludge Bomb (5 moves, pick 4 of 'em) ).

Since you don't have Poison/Ground-type, the male Nidoran that you can get by trading female Nidoran would be awesome.

Rate my team:

Zapdos level 73: Light Screen, Thunderbolt, Thunder, Drill Peck
Tyranitar level 73: Rock Slide, Crunch, Earthquake, Brick Break (Going to replace Brick Break with Bulk Up if I'm getting Heracross)
Charizard level 73: Dragon Claw, Fire Blast, Flamethrower, Fly
Lapras level 73: Surf, Hydro Pump, Ice Beam, Rain Dance (Confuse Ray would be kinda smart I guess, could replace Hydro Pump, Surf is kinda too good to pass I think)
Mewtwo level 73: Safeguard, Calm Mind, Recover, Psychic

6th pokemon at the moment is either Level 70 Victreebel (Sleep Powder, Growth, Solarbeam, Sunnyday)
or Level 61 Dragonite (Just leveled it up, gonna level further: Fly, Outrage (Dragon Claw already used), probably Ice Beam and Thunderbolt for the last 2 moves)

I'm not a professional with rating teams, this is just my point of view

Well, for my Pokémon mostly used to defeat the Champion's League. I hate to admit it but, I used a legendary which I hate doing, I used Articuno and it's Ice beam. I stocked up on PP restorers or whatever they are called and basically Spammed Ice Beam. But used Venusaur etc. I had a krabby on my team that was lvl 23 or so that I only use for surf, So they aren't that tough if I didn't need all of my Pokémon. Only used about 3 Pokémon to attack. So yeah I recommend Articuno with it's Ice Beam.