Yeh go with Triumphant, it is going to have lots of playable cards, such as Gengar Prime, Lost World, Hunter, recover energy, and any of those T/S/S would be so much fun to pull in reverse holo. Also it is going to be the newest set, therefore it will be in play for the longest out of all the sets listed and people will be looking to trade for the cards they need to complete the set, and you can get some quality cards for new primes. If you can't get Triumphant, Majestic Dawn, Rising Rivals, Platinum and Undaunted are all great sets as well. Also I wouldn't take a box of Arceus if someone gave it to me, the only cards I care about out of that set are Electrike # 63 and Trecko #78 and that is because I collect them. Stay as far away from Supreme Victors and Arceus as you can.