GP Minneapolis and GP Manchester
There were two Standard GPs on the last weekend, one in Minneapolis and one in Manchester.
The best deck
After a short break white is back in full force! There were two Standard Grand Prix on the last weekend, one in Minneapolis and one in Manchester. While there were various archetypes represented, you may have noticed that all eight decks in Minneapolis used some amount of white cards. Meanwhile in Manchester a massive two players managed to sneak into the Top8 without using white cards. The end result was the same though with G/W Tokens winning the title both times. G/W Tokens keeps delivering great results by being fast enough to keep up with Humans while their great planeswalker team keeps refilling the board against control decks. It's not the cheapest deck, but playing it seems to pay off in prizes nicely.
If you are more interested in innovation and fun than in winning though, there are still new decks to be found and optimized. Maybe you want to look into these deck lists to fine-tune them, or to pick up the key cards, hoping for those decks to become a major force in the near future.
The cool decks
Joel Larson summoned all kinds of Dragonlords with the almost forgotten Shaman of Forgotten Ways. While this sounds like fun, there won't be a great investment chance there, with all the key cards already rotating out in October. But there are other interesting opportunities:
I talked about the potential of Goldnight Castigator during the pre-sale phase, but red decks never became a thing due to white Humans being the better aggro deck. Tomaharu Saito may have found the right way to use a playset of Castigators now with the U/R Flyers deck he piloted to a 12-3 record in Minneapolis. Maybe this deck can be improved, maybe Castigator will see play in other deck shells now that she has been put on the map by Saito. As this card has just been released, there will still be lots of metagame permutations for it to potentially shine in.
Martin Müller came up with a different version of Mono Blue. He is using some of the same cards, but instead of focussing on Brain in a Jar, he is using Jace's Sanctum to turn all the slightly over-costed blue cards into something much more exciting. Following up a Time Walk with a Timetwister was a classic line twenty years ago, and Part the Waterveil into Day's Undoing even costs the same amount as the original duo once you have two Sanctums in play!
Day's Undoing has dropped to a very low price by now, and would see significant gains if it ever became widely used. Due to being a mythic and resembling the most iconic “draw 7”, it has decent casual long-term potential as well, so it has become a low risk, high reward card by now. You should definitely pick up some copies after rotation for its Modern potential.
Talking about Modern and new ideas: As malz77 pointed out in a recent comment, a new Tarmo Twin variant has recently been spotted. Grand Architect and Pili-Pala have been used in a classic RUG Tarmogoyf variant with Snapcaster Mage, Lightning Bolt and so on. These two unusual creatures can produce an arbitrarily large amount of coloured mana together, allowing you to draw your entire deck with Whispers of the Muse and still play all of your cards. From there winning should not be all that difficult. Both creatures can be found with Collected Company, but aren't very exciting without each other. While the fate of the deck or combo is still unknown, the cards are so cheap at the moment that it won't hurt to get them now.