Dryad Greenseeker With enough shuffling effects and topdeck manipulation (Sylvan Library) I can see Dryad Greenseeker as a neat source of card advantage at just 2cmc
Alternatively, cards with incredibly strong internal synergy, like Arcades, the Strategist or Tom Bombadil, are amazing in bracket three
While there are no precon decks for them, savvy players can build their own based on the characters' abilities
Both these cards are pre-selling in the $20-$25 range, and while I expect these to drop as well once Spider-Man is released, the fact that these are two iconic characters from the Spider-Man universe tells me these may retain at least some of this financial value ongoing
In Magic: The Gathering, sometimes you'll have a handful of rubbish, your best cards disobediently hiding somewhere within your deck
Heartbeat of Spring Heartbeat of Spring can help you ramp a lot, but it can also be a double-edged sword