Corridor Monitor [Double Masters] 283 Set: Sun & Moon: Lost

Set: Sun & Moon: Lost Thunder Type: Water Rarity: Common Retreat cost: Colorless

Set: Sword & Shield: Black Star Promos Type: Metal Rarity: Promo Retreat cost: Colorless

creatures you control get +2/+2

and I *have* tried

Set: Innistrad: Double Feature Type: Creature — Human Druid Rarity: Uncommon Cost: {1}{G} Reclusive Taxidermist gets +3/+2 as long as there are four or more creature cards in your graveyard

Corridor Monitor [Double Masters] 283 Set: Sun & Moon: LostSet: Double Masters Type: Artifact Creature Construct Rarity: Common Cost: {1}{U} When Corridor Monitor enters the battlefield, untap target artifact or creature you control. Castle Vantress has no locks on its doors, but interlopers rarely make it past the foyer.