+1/+1 counters are common buffs for all types of creatures in pretty much every MTG set, sagas track their progress with lore counters, planeswalkers add or subtract loyalty counters with their activated abilities and players can lose the game for acquiring too many poison counters, or stack up the energy counters from Kaladesh and Modern Horizons 3
The mono black deck is pretty much the same as it ever was, but with Sorin bolted on: Sheoldred, Orcish Bowmasters, and the Grief package all feature
He's often paired with the similarly generically strong Tymna the Weaver, and this dynamic duo is a mainstay in cEDH
Any tournament-specific rules in these Operations Documents will supersede directions given in this policy document
Played via the effect of "Plague Rounds", "OP04-047 Ice Oni" can shut down attacks by Characters of 5 cost or less, and even synergizes with your Leader effect