Futuroids sometimes come out of other chance events such as philosopher books and marvel. I have a number of futuroid coupons sitting unopened on my account. Idk if gachapon has them or not. If you keep checking the AH you may be able to purchase one.
Legendary Hero Potion = 30 att/matt for 2 hrs, they have to be crafted.
Monster Park gives coins that let you purchase pots that give 30 att for red and 30 matt for blue, for 30 min that stack with other att pots. They cost 5 coins each.
If you are lucky enough to know someone that has them, Witch's Special Stew gives 40 att for 15 min.
If your married in game and your lucky you can farm onyx apples every day in Amoria PQ. They give 100 att/matt for 10 min.
There are boss att pots that can be crafted if you know someone with very high Alchemy they give 10% and 20% boss att depending on what one.
There are Cold Winter Energy buffs that come from winter events they give 20 att/matt for 30 min.