The problem, of course, is that theyre strictly worse than Unknown Shores, which is hardly a staple
Julius Jumblemorph Ego Erasure Feisty Spikeling Firdoch Core Fire-Belly Changeling Flock Impostor Formless Genesis Game-Trail Changeling Gangly Stompling Ghostly Changeling Gladewalker Ritualist Graveshifter Guardian Gladewalker Impostor of the Sixth Pride Irregular Cohort Littjara Littjara Glade-Warden Littjara Kinseekers Masked Vandal Maskwood Nexus Mirror Entity Mischievous Sneakling Mistform Ultimus Mistwalker Moonglove Changeling Moritte of the Frost Morophon, the Boundless Mothdust Changeling Mutable Explorer Nameless Inversion Omni-Changeling Omo, Queen of Vesuva Overlord of the Hauntwoods Personify Prideful Feastling Realmwalker Rooftop Percher Runed Stalactite Shapesharer Shields of Velis Vel Sizzling Changeling Skeletal Changeling Springleaf Parade Stalactite Dagger Taurean Mauler Three Tree Mascot Turtleshell Changeling Universal Automaton Unsettled Mariner Valiant Changeling

Karametra, God of Harvests Karametra, God of Harvests leads landfall decks by turning every creature spell into a ramp spell
Plus, you're going to end up with 12 Sulfur Falls, 16 Chart a Course and Lava Coil, and some extra copies of Niv-Mizzet, Parun, which you can trade away or sell to recoup some value
Unfortunately, as her cost is only three, it limits which songs she can do this with, but this could still be a very powerful card when used well