Here in Round 4, things are beginning to stratify a bit. With the lack of byes at Team Grand Prix, there isn't a massive influx of new players with perfect records to really mess around with a midday glimpse around the top tables.
At Team Grand Prix, the card pools are so much larger than in individual Sealed Deck Grand Prix that the decks can begin to look wildly different. The good decks are good, and the bad decks are, well, still good, but not good. While each individual card pool is obviously going to be different, there are still some fairly apparent general strategies to Team Sealed Deck work with the full Theros block.
First off, to no one's surprise I'm sure, Red and Black appear to be the most restrictive colors in the format. It's hard to say that they're "the least played colors" since every team has a Red deck and a Black deck, but they certainly appear the least frequently and always with the same basic pairings. Red/Blue and Red/White seem to be significantly underrepresented in the field. Red/Green, however, has a fairly decent following, which I'll come back to in a minute. Black, on the other hand, is laughably in favor of Blue/Black. There are a smattering of Black/Red decks filling out the tables, but those decks are almost entirely from the limited number of pools that had a great Minotaur deck in their pool. Interestingly, there are a not-insignificant number of monocolored decks at the top tables, and they happen to be primarily Black or Red.
As for the other colors, there seems to be a fairly clear split between Blue, White, and Green as for the most populous color, and they appear to be a bit more promiscuous in their pairings. White is split primarily into White/Green and White/Blue decks. Blue is most heavily split between Blue/Green and Black/Blue. Meanwhile Green is found in the most color combinations, with only Black/Green underrepresented.
One of the reasons for this is the nature of the beasts. Moreso than any other color, Green has two faces. First is the heroic, "build your own monster" Green cards like Setessan Oathsworn, Staunch-Hearted Warriors, and the plethora of great Green tricks to enhance them. Next comes the actual monsters, the beefy Green beaters that can be so hard to deal with in this format. Finally, there are all of the mana producers and ramp cards that Green has to offer, such as Font of Fertility, Voyaging Satyr, and Golden Hind. The heroic deck and the mana deck tend to represent opposing strategies, while the beasts are ideal complements to the initial heroic aggro as well as end-game threats for the ramp decks.
That brings up another good point: because of the size of the card pools in Team tournaments, decks are incredibly focused. You don't often see a Black/Red deck with a Minotaur subtheme the way you would in solo Sealed Deck or Booster Draft. You see a Black/Red Minotaur deck. When you see heroic decks, they are the most streamlined, linear versions of the deck you can imagine. The ramp decks are consistently throwing down fatties on turn four. These decks are legit. Because of this fact, decks need to be as streamlined as possible. Cards that don't help the deck's theme, like mana ramp cards in a heroic deck, need to find another home.
Getting back to Green, it is by far the most split up color within individual card pools. This multifaceted nature of the color lends itself quite well to being split up. White and Blue are also being split up a reasonable amount themselves. White's cards, just like Green's, can find their way into multiple decks. In addition to the large number of Green/White heroic decks and the smattering of Blue/White heroic decks, there are a number of Blue/White control decks that are using White's great fliers and reasonable defensive creatures to fill the void when Blue/Black is unavailable. Blue, meanwhile, can really fit its way into any other shell, with the tempo cards and fliers teaming up well with Green's fat ground guys, anything White wants to do, and Black's great defensive cards.
In total, it looks, unsurprisingly, like the common conceptions about Team Limited in this format are roughly the same as what is seen in individual Limited, but with a bit of a sharper edge. The decks that are doing the best are the ones that have been focused, with no cards out of place. Obviously a few bombs never hurt anyone, but it is the proper allocation of cards and division of colors that appears to be winning the day here in São Paulo.