28 cards where the illustration contains “hydromancy”

Balduvian Conjurer (Ice Age #58)
Blue Elemental Blast (Signature Spellbook: Jace #2)
Burrog Befuddler (Strixhaven: School of Mages #38)
Cascade Seer (Zendikar Rising #48)
Counterspell (Duel Decks: Jace vs. Chandra #24)
Deflection (Seventh Edition #69)
Fathom Mage (Gatecrash Promos #162★)
Frantic Firebolt (Wilds of Eldraine #130)
Frolicking Familiar // Blow Off Steam (Wilds of Eldraine #226)
Hydroblast (Magic Online Promos #69979)
Hydrolash (Magic Origins #59)
I Know All, I See All (Archenemy Schemes #18★)
Ingenious Mastery (Strixhaven: School of Mages #44)
Johann, Apprentice Sorcerer (Wilds of Eldraine #207)
Kiora's Dismissal (Journey into Nyx #44)
Lifetap (Fifth Edition #99)
Nicanzil, Current Conductor (The Lost Caverns of Ixalan #236)
Part Water (Legends #66)
Quiet Contemplation (Khans of Tarkir #50)
Restless Spire (Wilds of Eldraine #306)
River's Favor (Arena New Player Experience Cards #19)
Saji's Torrent (Sega Dreamcast Cards #8)
The Apprentice's Folly (Wilds of Eldraine #200)
Tidebinder Mage (Magic 2014 #73)
Veyran, Voice of Duality (Commander 2021 #3)
Water Wings (Wilds of Eldraine #77)
Wave Elemental (Mirage #102)
World Shaper (Rivals of Ixalan #151)

Though this query has ended, its relics still slumber in New Argive.