This can be any kind of counters: +1/+1 counters on creatures, loyalty counters on planeswalkers, even unusual things like time, charge, or doom counters
Core Rat Staples Every Deck Wants These cards form the backbone of nearly every rat deck regardless of which commander sits at the helm
Humans went on to be a potent type since they're so common in Magic
The primary commander is Morska, Undersea Sleuth, a reasonable but maybe low-power commander that generates a Clue each turn and gets bigger if youre able to consistently draw extra cards
The first place I look is my LGS
Most cards in this deck get better the more you have, like Hunting Pack to rapidly fill your board through Storm, Magmatic Force to generate continuous value, and Ray of Command to make your opponents wish they never played the game in the first place