Punch card

Punch cards are perforated cards that can be punched out into small cardboard markers that can be placed on playing cards.

History
Punch cards were introduced in the official Magic game in the Amonkhet block as a playing aid to keep track of abilities or counters added to regular cards, or to replace token cards in limited environments.

Punch cards were considered to be a success, but R&D announced that they didn't plan to do punch cards for every set, as they considered it a tool rather than something they wished to rely on repeatedly. Punch cards returned with Ikoria: Lair of Behemoths where they featured keyword counters.

Mark Rosewater considers the design potential for punch-out technology "pretty huge".

Amonkhet block

 * Embalm
 * Eternalize
 * Exert
 * -1/-1 counter
 * Brick counter

Ikora: Lair of Behemoths and Commander 2020

 * +1/+1 counter
 * Keyword counters