Cycle Harvest

Rare attack
Deal 4 damage. Spend all Growth: +3 damage per Growth.
Become what survives.
A keeper of lost seasons who borrows predatory, guardian, and grove forms.

Fight in one of three forms: Guardian (bear) adds Block, Thorns and Counter; Stalker (cat) adds damage and Bleed; Grove adds healing, draw and Growth. A card's form bonus is added on top while you are in that form. Your first shift each turn grants 1 Growth. Cards that say Spend Growth use it for extra damage, Block or healing. Growth caps at 6 and persists.
Every Druid run begins with these ten cards.

Rare attack
Deal 4 damage. Spend all Growth: +3 damage per Growth.

Rare skill
Draw 2 cards. Shift to the next form (Grove → Guardian → Stalker → Grove). Gain 1 Growth. Your first shift each turn grants 1 Growth.

Rare attack
Shift to the next form (Grove → Guardian → Stalker → Grove). Deal 6 damage. Spend up to 2 Growth: +3 damage per Growth. Your first shift each turn grants 1 Growth.

Rare attack
Shift to Stalker. Deal 7 damage. If you shifted this turn: +3 damage. Your first shift each turn grants 1 Growth.
At the start of a run, and again at the start of each new act, you choose one of three Disciplines. They last for the rest of the run.
Stay in Grove to draw and build Growth with Seedwake and Starseed. Spend it all on Cycle Harvest for a finishing blow, or on Seasonal Promise to heal. Under the moon, Moonsear and Falling Heavens leave foes Moonburned and Starbreak turns Growth into one great blow.
Key cards: Starseed, Grove Secret, Cycle Harvest, Rootstorm, Wild Renewal, Seasonal Promise, Seedwake, Moonsear, Moonrise Vigil, Starbreak, Falling Heavens.
Disciplines that fit: Deep Grove, Renewal.
Shift into Guardian so Block cards get their Guardian bonus. Bark Mantle turns stored Growth into Block; Briarcrown adds Thorns and Counter in Guardian.
Key cards: Bramble Ward, Bark Mantle, Thistle Circle, Wild Renewal, Season's Turn, Seasonal Promise, Briarcrown, Briarhide Sweep.
Disciplines that fit: Living Bark, Cycle Advocate.
Shift before striking: Predator's Answer and Primal Wake hit harder once you have shifted this turn, and Stalker bonuses add Bleed. Wild Spiral turns Growth into damage.
Key cards: Rake, Fang of Winter, Predator's Answer, Wild Spiral, Primal Wake, Season's Turn, Moonlit Pounce, Rending Sweep, Duskfall Comet.
Disciplines that fit: Wild Memory, Red Fang, Cycle Advocate.