Take a large double striker, like say Blast-Furnace Hellkite, and suddenly someone is dead with the help of Tainted Strike
A common procedure for when the round timer expires is to call the current turn, turn zero, and then after five turns, the game ends, if neither player has won, it is a draw

Here they are: Dual Lands Underground Sea: Grixis Control, U/B Deaths Shadow, Grixis Delver, Ad Nauseam Tendrils, Esper Stoneblade Volcanic Island: Grixis Control, Sneak and Show, Grixis Delver, Temur Delver, Ad Nauseam Tendrils Bayou: B/R Reanimator, Ad Nauseam Tendrils, Four-Color Loam, Turbo Depths Badlands: Grixis Control, B/R Reanimator, Four-Color Loam Tropical Island: Temur Delver, Infect Tundra: Miracles, U/W Stoneblade Scrubland: Four-Color Loam, Esper Stoneblade Savannah: Four-Color Loam Taiga: Lands, Four-Color Loam Other Cards City of Traitors: Sneak and Show, Eldrazi Stompy, Affinity, Mono-Red Prison The Tabernacle at Pendrell Vale: Lands, Four-Color Loam Intuition: Sneak and Show Null Rod: Miracles, Grixis Delver Lions Eye Diamond: Ad Nauseam Tendrils Mox Diamond: Lands, Four-Color Loam Drop of Honey: Lands Grim Monolith: Eldrazi Post Gilded Drake: Merfolk This list is eighteen cards long

Legendary Creature - Vampire Noble Commander (CTRL to add secondary) Anthem Anthem (CTRL to add secondary) Artifact Ceremonial Knife Equipped creature gets +1/+0 and has "Whenever this creature deals combat damage, create a Blood token." (It's an artifact with ", , Discard a card, Sacrifice this token: Draw a card.") Equip (: Attach to target creature you control
Most other variants are worth around $1