Infect is a mechanic that does this pretty well, but you can also use spells such as target creature gets -2/-2 until end of turn or something similar
One wrinkle: Wizards current Brawl format page lists 100-card Brawl with 25 life and 1v1 play on Arena, while other official explainer content describes Brawl as 60-card

Daybound/Nightbound Card Gallery and List Arlinn, the Pack's Hope / Arlinn, the Moon's Fury Baneblade Scoundrel / Baneclaw Marauder Bird Admirer / Wing Shredder Brutal Cathar / Moonrage Brute Burly Breaker / Dire-Strain Demolisher Curse of Leeches / Leeching Lurker Fangblade Brigand / Fangblade Eviscerator Graveyard Trespasser / Graveyard Glutton Harvesttide Infiltrator / Harvesttide Assailant Hound Tamer / Untamed Pup Kessig Naturalist / Lord of the Ulvenwald Outland Liberator / Frenzied Trapbreaker Reckless Stormseeker / Storm-Charged Slasher Shady Traveler / Stalking Predator Spellrune Painter / Spellrune Howler Suspicious Stowaway / Seafaring Werewolf Tavern Ruffian / Tavern Smasher Tireless Hauler / Dire-Strain Brawler Tovolar, Dire Overlord / Tovolar, the Midnight Scourge Tovolar's Huntmaster / Tovolar's Packleader Village Watch / Village Reavers Other Cards That Interact With Day/Night: Angel of Eternal Dawn Celestus Sanctifier Gavony Dawnguard Component Collector Firmament Sage Brimstone Vandal Obsessive Astronomer Olivia's Midnight Ambush Moonrager's Slash Sunstreak Phoenix Sunrise Cavalier Unnatural Moonrise Vadrik, Astral Archmage The Celestus So You Wanna Play Werewolves

Once you have nine or more creatures, he provides a massive buff that can end the game instantly
View full PSA Population Report Cards related to "Oddish".
When this card is destroyed, draw 1 card for every other Zone Master card you control