Hero card

Collector's Cage

Artifact

Value on arrivalDoes its thing as it enters: worth it from the first moment

Needs: Valiant

Gives: Counter +1/+1, Artifacts

Not in winning lists yet: read from the card text and the graph

Build a deck with Collector's Cage as the hero

Makes it work

Seedglaive Mentor

Benefits from it

Costume Closet · Tidus, Blitzball Star · Dockworker Drone · Donatello, Way with Machines · Builder's Talent · Solitary Sanctuary · Selfless Police Captain · Crime-Scene Instructor

Use instead if you don't have it

Costume Closet · Agatha's Soul Cauldron · Explorer's Cache · Astrologian's Planisphere · Dockworker Drone · Lost Jitte

Cards in the meta that answer it

Countersculpt (Azorius Control) · Inevitable Defeat (4-Color Control) · No More Lies (Azorius Control) · We Say Thee Nay! (Dimir Aggro)