Ixalan Checklist Token (TXLN) from Ixalan, available at 401 Games Canada.

• Rarity: Token
• Finish: Normal
• Card Text:
  You can mark this card to represent a double-faced card in your library or hand.
  Legion's Landing W
  Search for Azcanta 1U
  Arguel's Blood Fast 1B
  Vance's Blasting Cannons 3R
  Growing Rites of Itlimoc 2G
  Conqueror's Galleon 4
  Dowsing Dagger 2
  Primal Amulet 4
  Thaumatic Compass 2
  Treasure Map 2