Deck: Temur Emerge, because I think it has an above 50% matchup against every deck in the format at the moment. Emrakul is also fun.
Most useful sideboard card: Wretched Gryff
What was the most interesting play you saw or made this weekend?
I played Emrakul against my opponent's Emrakul into Mindslaver to Transverse for a Distended Mindbend to sacrifice his Emrakul, which lead to me winning the match. I started that game with 1 land and I only had 3 lands by the time my opponent managed to get a Liliana emblem out.
What is the best Standard deck in your opinion (that you did not play yourself)?
I think there are plenty of decks that are equally good in Standard at the moment.