Blood Artist, Mayhem Devil, and Midnight Reaper are excellent examples
While we've had some commanders like Davros and Tivit make use of it, Cirdan from the Lord of the Rings Elf Commander deck uses diplomacy to give your opponents lots of treats
A lot of artifact strategies rely on cheap artifacts to get rolling, so playing Meltdown for 2 mana and wiping out multiple cards on an opposing player's board is very reasonable, sometimes bordering on game-winning
Kefka, Court Mage // Kefka, Ruler of Ruin Rarity: Mythic Rare TYPE: Legendary Creature // Legendary Creature SUBTYPE: Human Wizard // Avatar Wizard CMC: 5 Mana cost: USD: $5.07 EUR: 5.42 TIX: 0.03 EDHREC RANK: 3169 (4/5) Whenever Kefka enters or attacks, each player discards a card
In each case, the following turn would return the state of the game to Day