Putting into play and casting without paying its mana cost are different things even though they seem very similar
This was the first set to feature legendary creatures (which were simply dubbed Legends at this point, with no other creature types) and also marked the debut of 15-card booster packs in boxes
These cards allow players to invest mana to reach new "levels" of enchantment power, albeit using a cleaner, Saga-style frame and starting at level 1 instead of 0
Valor's Reach Valor's Reach is such an odd card, which is why it rounds out the honorable mentions here
11 Inscription of Abundance Modal Fight Spell With Strong Kicker Ability Part of the inscription Sultai (black, green, and blue) cycle of cards from Zendikar Rising, this modal spell includes two creatures fighting one another as one of its modes
That is the "playmat premium" you find on ticket prices, and frankly why you do not see many of them for sale "in the wild" right now: for most of the player base it simply makes sense to get as many non-foil promos as possible and sell them quickly at or below market value without having to put all your eggs into the playmat basket