12 cards where the text includes “dredge” and the set is “rav”

Darkblast (Ravnica: City of Guilds #82)
Golgari Brownscale (Ravnica: City of Guilds #166)
Golgari Grave-Troll (Ravnica: City of Guilds #167)
Golgari Thug (Ravnica: City of Guilds #87)
Grave-Shell Scarab (Ravnica: City of Guilds #211)
Greater Mossdog (Ravnica: City of Guilds #169)
Life from the Loam (Ravnica: City of Guilds #172)
Moldervine Cloak (Ravnica: City of Guilds #173)
Necroplasm (Ravnica: City of Guilds #98)
Nightmare Void (Ravnica: City of Guilds #100)
Shambling Shell (Ravnica: City of Guilds #230)
Stinkweed Imp (Ravnica: City of Guilds #107)

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