you may play cards from exile mtg Hedonist's Trove Top 30 Exile-Play Red Cards

It will be very good in that deck, casting a free two-CMC-or-less spell every time it connects, but you cant recast the same spell due to the exile clause

I also think this card is a bit underplayed

10: Jason Chan ( Jason Chan has worked on some of Magics most powerful cards in recent times such as Avacyn, Angel of Hope and Jace, the Mind Sculptor as well as cards like both versions of Xenagos and Deicide above

If the creature this Aura would enchant is an illegal target by the time Knightly Valor tries to resolve, the Aura spell doesn't resolve

Timing will be critical when playing this card

The new set has already had a significant impact on Standard, and this will become even clearer once we see the full lineup for the event