BW Megatron was a loadbarer in the prequel comic, so...

 

Beast Wars Megatron
Armada Starscream
G1 Soundwave
Prime Shockwave
Animated Slipstream
Fall of Cybertron Bruticus
Animated Lugnut & Animated Blitzwing

 

g1 megatron
g1 starscream
g1 soundwave
idw g1 shockwave
g1 skywarp
g1 1986 movie devastator
g2 roadblock and dirtbag

 

yeesh, that sounds like a team more likely to turn on and murder each other than work together cohesively and win

 

took a while but its done

sg megatron
end of armada starscream
knights of unicron soundwave
cybertron shockwave
early animated blackarachnia
g1 blitzwing
g1 octane and g1 jetfire

 

Alternity decepticons.

 

Prime Megatron
Cybertron (GF) Starscream
G1 Soundwave
Prime Shockwave
Cyberverse Slipstream
FoC Bruticus
Goon 1 Cybertron Sideways (GF Noisemaze)
Goon2 Prime Knockout

 

Soundwave, and all his minions.

All the Soundwaves, and all the minions. You know, ever version.

There, that's the team. All Soundwaves and his minions.

 

All right, then I dibs the army of reflectors from Siege.

WE... WE WILL BE UNSTOPPABLE!!!!!!!!!!!

 

Right, right, include all the reflectors as well. Sounds excellent. Soundwave's will be their own army.

 

Megatron: Armada Megatron
- Selected for high chonk content, and for successfully entraining Scorponok's style. Green really works on Megatron!

Starscream: Transformers Prime Starscream
- He has a good balance between conniving and capability, with a wonderfully evil style. Time has matured him slightly and he is better at waiting

Soundwave: Cyberverse Soundwave
- Has a great voice. One of the most direct Soundwaves, with an armored truck alt mode and a penchant for butting heads.

Shockwave: G1 Cartoon Shockwave
- So loyal, he assumed Megatron was alive and would return for over 4 million years, and kept things running. Every unit needs a reliable Egghead\Energon Accountant.

Fembot: Cyberverse Clobber
- Because doors are for suckers. This squad will ALWAYS make a smashing entrance! She can defeat most stationary targets--such as walls--by driving toward them.

Brute: G1 Cartoon Sixshot
- The six-changing anti-combiner specialist. A fuel-efficient alternative to choices like Devastator, but with similar firepower... He will not be hassled by smaller, more agile bots, either.

Goons: G1 Cartoon Hound and Mirage.
- The tactical potential of these characters is just broken as hell, and they have a great pair dynamic.

 

Has there ever been a Decepticon team to work cohesively?

 

The core four that stayed with Master Megatron in Cybertron (Thundercracker, Ransack, Crumplezone, Thunderblast) and that was a show where a lot of bots changed sides.

 

Thunderblast left Galvatron’s Decepticon team for awhile to join Starscream’s group. Thundercracker was the only real one.

 

Megatron
Cyclonus
Shockwave
Galvatron
Deathsaurus
Nemesis Prime- can't forget him
Tarn
Thunderwing
Overload

 

Your pfp lol

 

The new Decepticon High Command.

BW Megatron
Prime Soundwave
Armada Starscream
IDW Shockwave

 

Cybertron Master Megatron: incredibly powerful and quite cunning. Prefers to let his goons handle things, but is not afraid to get his hands dirty.
Armada Starscream: capable swordsman and debatably even better than his own series Megatron.
G1 Soundwave: not the strongest version of this character, but he's great at his job, which is all he needs to do with teammates this good.
Devastation Shockwave: his boss fight is awesome, nuff said.
female decepticon: Animated Slipstream, on account of being stronger than the only other female con i know (Thunderblast).
heavy hitter: Animated Lugnut. dudes insane, could solo most combiners.

goons: Headmasters Sixshot and 01 Sky-Byte. Both of them are hilarious, and the Ninja Consultant isnt a total pushover either.

 

Minor quip about asking for a powerhouse team, then requiring certain characters to be on it, but moving on, going strictly as intended:

Megatron Omega
Energon Starscream
G1 Sunbow Soundwave
Cyberverse Shockwave
Cyberverse Shadow Striker
Abomenaticus
TFA Lugnut
IDW Tarn


Bending the rules a bit:
Marvel Galvatron
Gilthor
Headmasters Soundblaster
Onyx Prime
Megatronia
Black Zarak
IDW Sixshot
Car Robots Black Convoy

 

I'm working on the assumption Predacons and Vehicons aren't allowed.

Animated Megatron: I put the most emphasis on Megatron's smarts and Animated Megatron knew when to play it smart. He didn't let ego get in his way and was willing to lay low and play the long game.

TF1 Starscream: In all honesty, as much as a scheming traitor is an integral part of the dynamic of any Transformers fiction's villain, it tends to hold them back. For this reason, I've chosen a screamer who, prior to retcons, never showed any real signs of treachery and was shown to be a formidable areal warrior.

Sunbow Soundwave: On numerous occasions, this Soundwave was shown to be a capable warrior, plus had the largest array of gadgets and abilities of any Soundwave and the highest number of cassetticons.

Animated Shockwave: While far from my favorite characterization of Shockwave, I think his disguise ability is the most unique and valuable asset that any version of the character has to contribute.

Prime Airachnid: She can offer a lot as a stealthy predator and while she is treacherous, her schemes were never really great enough to adversely effect the Decepticons to any serious degree.

IDW Sixshot: Capable of leveling a planet, he is one of the single most powerful Decepticons to have been featured in a Transformers story. Although far from loyal to the Decepticon cause, he is a far less effective schemer than Overlord, meaning his built-in shutdown command can easily keep him under control. Additionally, his six-change ability grants him far greater versatility.

Prime Knockout & Breakdown: While I was never fond of Knockout being used as a standard henchman, with how the mere idea of blemishing his appearance was enough to scare him off, I do think it's important to have Surgeons on the Decepticon side. For that reason, I'm including this duo.