An obvious example would be something like Relentless Rats that revolves around the player's ability to get a number of them
This can work in control as well as agro as a 3 power evasion monster is a reasonable threat at any stage of the game, and for the bargain cost of one mana does not leave you vulnerable in order to get it out

List of Showcase Woodland Cards in Bloomburrow Dawn's Truce Jackdaw Savior Salvation Swan Starfall Invocation Valley Questcaller Warren Warleader Whiskervale Forerunner Azure Beastbinder Dour Port-Mage Kitsa, Otterball Elite Mockingbird Portent of Calamity Thundertrap Trainer Valley Floodcaller Coiling Rebirth Cruelclaw's Heist Darkstar Augur Osteomancer Adept Valley Rotcaller Wick, the Whorled Mind Emberheart Challenger Festival of Embers Hired Claw Manifold Mouse Stormsplitter Valley Flamecaller For the Common Good Keen-Eyed Curator Mistbreath Elder Scrapshooter Tender Wildguide Valley Mightcaller Kastral, the Windcrested The Infamous Cruelclaw Hugs, Grisly Guardian Finneas, Ace Archer Alania, Divergent Storm Camellia, the Seedmiser Mabel, Heir to Cragflame Clement, the Worrywort Helga, Skittish Seer Glarb, Calamity's Augur Are Showcase Woodland Cards in Play Boosters

1 Mana Drain - Textured Foil Breaking News - $241.11 Countering a spell always feels good in a Magic game, but countering one and then getting refunded a bunch of mana on your next turn feels even better
Harpy Lady Archetype Amazoness Archetype Guardians Archetype Basic Insects and Insect Support Summon Sorceress Bakura Bakura's pack is a bit of a mixed bag
Recycle [1st Edition] #61 Pokemon Fossil Keep track of your collection value over time