If you don't, at the beginning of the next end step, return that card to the battlefield under its owner's control with a vigilance counter and a lifelink counter on it
Imagine that every time I sell a card, I am making 7.5x on my investment

31%inclusion 30%synergy 5.65K decks 18.2K decks Waterbender's Restoration 31%inclusion 29%synergy 5.38K decks 17.5K decks Swords to Plowshares 30%inclusion -8%synergy 5.49K decks 18.3K decks Heroic Intervention 28%inclusion 5%synergy 5.12K decks 18.3K decks Earthshape 27%inclusion 26%synergy 4.80K decks 17.5K decks Abandon Attachments 24%inclusion 22%synergy 4.28K decks 18.2K decks Energybending 21%inclusion 20%synergy 3.75K decks 17.7K decks Path to Exile 18%inclusion -11%synergy 3.35K decks 18.3K decks Deflecting Swat 18%inclusion 7%synergy 3.25K decks 18.3K decks Firebending Lesson 17%inclusion 16%synergy 2.99K decks 17.4K decks The Last Agni Kai 16%inclusion 16%synergy 2.90K decks 17.7K decks Accumulate Wisdom 16%inclusion 15%synergy 2.85K decks 17.5K decks Octopus Form 16%inclusion 15%synergy 2.88K decks 17.6K decks Elemental Teachings 15%inclusion 14%synergy 2.61K decks 17.5K decks Counterspell 15%inclusion -9%synergy 2.66K decks 18.3K decks Flawless Maneuver 13%inclusion 9%synergy 2.37K decks 18.3K decks Allies at Last 12%inclusion 11%synergy 2.13K decks 17.6K decks Deadly Rollick 11%inclusion 6%synergy 2.07K decks 18.3K decks Searing Touch 11%inclusion 11%synergy 2.06K decks 18.3K decks Eladamri's Call 11%inclusion 6%synergy 2.05K decks 18.3K decks Sandbenders' Storm 11%inclusion 10%synergy 1.88K decks 17.5K decks Combustion Technique 8.9%inclusion 8%synergy 1.56K decks 17.5K decks Katara's Reversal 8.6%inclusion 8%synergy 1.52K decks 17.6K decks Obscuring Haze 7.9%inclusion 7%synergy 1.44K decks 18.3K decks Whirlwind Technique 7.9%inclusion 7%synergy 1.38K decks 17.5K decks Sokka's Haiku 7.9%inclusion 7%synergy 1.43K decks 18.2K decks Force of Negation 7.7%inclusion 4%synergy 1.41K decks 18.3K decks Fire Nation Attacks 7.3%inclusion 7%synergy 1.33K decks 18.2K decks Yip Yip

There are also scaling threats that get stronger with each discard
(9/20/2024) If a face-down spell leaves the stack and goes to any zone other than the battlefield (if it was countered, for example), you must reveal it
Sure, it sucks to open with Colress as your only Supporter, but it can be a savior late in the game when all you have floating around in your deck are Ns