Effects that allow you to cast a spell for an alternative cost or without paying its mana cost may allow you to apply those to the Adventure.
"The mechanic can fit well into a variety of aggressive decks
Alchemy is a reasonable analogue to Mystical Teachings, but only because it interacts with sorceries, creatures, planeswalkers, enchantments, artifacts, and lands
Perhaps that's why this set is so fondly remembered
9 Skewer The Critics Skewer the Critics may be a sorcery spell to make it harder to choose to use it on a creature rather than the opponent, but it's still a fantastic burn spell
Twilight ProphetTwilight Prophet While there are a ton of playables in this list, I do find myself nodding my head along to a different deck's beat, given that the deck I'm trying to build is trying to stay as low to the ground as possible, with as many two-drops I can play for one as possible