I would like to nominate:
@ Salac Berry
252 Atk/ 252 Spd/4 Hp
This set for terrakion is a fantastic set due to the changes of the black and white metagame from the release of berries. Terrak is really easy to build around as well, you have spin blockers like Gengar that take care of its fighting and ground weaknesses and you can use a Sr Tyranitar to set up the sand and be a good counter for the Psychic weaknesses. It also pairs up with LO Sheer force landorus for a good sp.attacker.
Now for the fun part- why the set is so good:
1st of all we all hate the Scarf Terrakions and Banded terrakions. This is a set combining both if we play our cards right and becoming a Scarf Double band mon. I know that sounds really silly but I think we all know where that comes from. +2 attack and +1 speed outspeeds most of the metagame barring Scarf latios, Scarf Gengar, Scarf Alakazam and such. But, we will have Tyranitar for that! So it's a great mon to base a team around in my opinion.