The OG Protagonists. The Strongest Three. The Battle Legends themselves. I'm pretty sure you can already see the pattern in these three but I will explain nonetheless. Their first Pokemon is their Partner Pokemon (Don't you dare tell me Clefairy doesn't deserve her own LG Version). Second and Third Pokemon are filler team members and the last 3 are the Original Three Kanto Starters. The difference is, the last slot is for their Mega Capable Pokemon, and it varies according to the trainer, befitting their color version name. Oh, and to clarify, Red's Charizard Mega Evolves into its X form.
It's Lance. I gave him Shiny Gyarados and Shiny Haxorus, because let's be honest; he would definitely end up getting them. The three Dragonites are because it would not be Lance otherwise. And Charizard is his Mega Capable Pokemon and it Mega Evolves into its X form.
Let's be real here, these are definitely the succesors of Lance. The main protagonists of the GSC games. Like their predecesors; Ethan, Kris and Lyra possess all three Original Johto Starters as the last three slots and a Partner Pokemon as their first slot. However, unlike their predecesors, they also Possess a Legendary in their Third Slot and a Togekiss in their second slot. As for their Last Slot Starter, they would be their potential Mega Capable Pokemon if a Mega Evolution of the Johto Starters were to come out.
And then there's Silver. After finally understanding that strength must be accompanied with compassion, he has had made leaps and bounds on his progress. Enough to actually defeat Lance and attain the Champion title. That said; he cares not for the title so much as having a tangible proof that he is growing stronger, so he leaves Lance as the official champion.
Is that a Shiny Metagross!? Why yes, yes it is. It's also Mega Capable. I don't think I need to explain why I gave him a Shiny Metagross, right?
Do not mistake grace and elegance for weakness. Wallace's Water Types also happen to pack one heck of a wallop. Swampert is his Mega Capable Pokemon.
The arrangement of these three is a bit different than their Protagonist predecessors, so I'll break it down per character.
Brendan has Plusle as his Partner Pokemon and both Latios and Rayquaza (Brendan is canonically the Player Character) as his Legendary Pokemon. His semi-final slot is for his Sceptile, which is Mega Capable. The rest of the team are filler Pokemon members. He does look like he prefers Grass-Types, huh? A Grass-Type Champion is not something you see every day.
May for her part, proves that being the Professor's daughter (Game continuity here) comes with its perks. She has Minun as her Partner Pokemon, Latias as her Legendary Pokemon and all three Original Hoenn Starters as her last 3 slots, with Wigglytuff filling the last slot. Marshtomp is her Mega Capable Pokemon. She has the most well-rounded team out of all the protagonists with a wide coverage of 10 types.
Wally has come a long way from his frail and humble beginnings (that sprite looks too old for him, in my opinion). With Ralts as his starter, it has now become his trustworthy, and Mega Capable, Gallade. He also has a Gardevoir and an Alakazam on his team, might he be partial towards Psychic-Types due to his Starter Pokemon? Who knows? Filling the rest of his team slot are his Altaria, Roserade and Magnezone.
It's Cynthia. Honestly, her team was already stacked as it was, with a whopping coverage of 11 types. And also, it's Cynthia, so
of course her Garchomp is Mega Capable.
Again, three protagonists; this time from Sinnoh. Their teams have similarities but also notable differences as I'll explain below.
Dawn has two legendaries like Brendan, since she is, canonically, the Player Character and thus, she gets Giratina and as the Player Character she is also the Bearer of Emotion. Buneary is her Partner Pokemon and Torterra is, should a Mega Evolution be made for it, her designated Mega Capable Pokemon.
She is the one Cynthia talks about during B2W2 when you fight her.
Lucas is a Professor's Assistant and well noted to be a voracious bookworm, and accordingly he gets to be the Bearer of Knowledge. His Partner Pokemon is a Riolu and, once again, being close to a Professor has its perks. He possesses all three Original Sinnoh Starters and Infernape is, should a Mega Evolution be made for it, his designated Mega Capable Pokemon.
Barry is the son of a Frontier Brain, and possesses all the amazing talent and potential at Pokemon training and battling that it implies. Do not let his spazzy and clumsy nature fool you, this guy's strength of character and mental fortitude is second to none; which is why he was chosen as the Bearer of Willpower. His team is composed of some serious heavy hitters of varied types in order to take on any challenge. Empoleon is, should a Mega Evolution be made for it, his designated Mega Capable Pokemon. Once again, do not let his demeanour fool you; his battle prowess is noted to be on par with the three Battle Legends themselves.
It's Alder with an improved team. Shiny Dragonite and Shiny Garchomp reference a certain event after completing the B2W2 post-game. The rest of his team, however, remains the same. Don't expect an easy battle this time.
Two Haxorus and Two Pseudo-Legendaries make Iris a formidable presence. Her Excadrill will also be a rude awakening for those who think they can simply sweep her off with an Ice or Fairy.