75 Magic: The Gathering cards
Showing a single ownership pip over a copy of Opt when a player could play four copies was not conveying useful information
4 Perennation = Cant Lose Secnario Standard/Commander Maybe less of a combo and more of a strategy, but no less effective when it comes to winning a game, the combination of Prennation and Herald of Eternal Dawn can stall out a game in your favor and put your opponents in an inevitable loss situation

Full Decklist: 3 Mountain 4 Forest 4 Island Arcane Signet Beast Within Become the Pilot Bigger on the Inside Bill Potts Carpet of Flowers Chaos Warp Cinder Glade Clara Oswald Command Tower Confession Dial Cultivate Cursed Mirror Dan Lewis Danny Pink Decaying Time Loop Desolate Lighthouse Dreamroot Cascade Exotic Orchard Farseek Fiery Islet Flaming Tyrannosaurus Flatline Frontier Bivouac Frost Fair Lure Fish Frostboil Snarl Fugitive of the Judoon Gallifrey Council Chamber Game Trail Graham O'Brien Growth Spiral Heaven Sent Impending Flux Into the Time Vortex Iraxxa, Empress of Mars Jenny Flint Karvanista, Loyal Lupari Last Night Together Lunar Hatchling Madame Vastra Me, the Immortal Memory Worm Myriad Landscape Nardole, Resourceful Cyborg Ominous Cemetery Osgood, Operation Double Path of Ancestry Ponder Preordain Psychic Paper Quantum Misalignment Reliquary Tower Return the Past River Song River Song's Diary Rockfall Vale Rogue's Passage Rootbound Crag Ryan Sinclair Search for Tomorrow Sheltered Thicket Sisterhood of Karn Sol Ring Sonic Screwdriver Start the TARDIS Stormcarved Coast Strax, Sontaran Nurse Surge of Brilliance Talisman of Curiosity Talisman of Impulse TARDIS Temple of Abandon Temple of Epiphany Temple of Mystery Temple of the False God The Flux The Foretold Soldier The Fugitive Doctor The Thirteenth Doctor The Twelfth Doctor Thijarian Witness Think Twice Throes of Chaos Truth or Consequences Twice Upon a Time Vineglimmer Snarl Waterlogged Grove Wreck and Rebuild Yasmin Khan 3 Mountain 4 Forest 4 Island Arcane Signet Beast Within Become the Pilot Bigger on the Inside Bill Potts Carpet of Flowers Chaos Warp Cinder Glade Clara Oswald Command Tower Confession Dial Cultivate Cursed Mirror Dan Lewis Danny Pink Decaying Time Loop Desolate Lighthouse Dreamroot Cascade Exotic Orchard Farseek Fiery Islet Flaming Tyrannosaurus Flatline Frontier Bivouac Frost Fair Lure Fish Frostboil Snarl Fugitive of the Judoon Gallifrey Council Chamber Game Trail Graham O'Brien Growth Spiral Heaven Sent Impending Flux Into the Time Vortex Iraxxa, Empress of Mars Jenny Flint Karvanista, Loyal Lupari Last Night Together Lunar Hatchling Madame Vastra Me, the Immortal Memory Worm Myriad Landscape Nardole, Resourceful Cyborg Ominous Cemetery Osgood, Operation Double Path of Ancestry Ponder Preordain Psychic Paper Quantum Misalignment Reliquary Tower Return the Past River Song River Song's Diary Rockfall Vale Rogue's Passage Rootbound Crag Ryan Sinclair Search for Tomorrow Sheltered Thicket Sisterhood of Karn Sol Ring Sonic Screwdriver Start the TARDIS Stormcarved Coast Strax, Sontaran Nurse Surge of Brilliance Talisman of Curiosity Talisman of Impulse TARDIS Temple of Abandon Temple of Epiphany Temple of Mystery Temple of the False God The Flux The Foretold Soldier The Fugitive Doctor The Thirteenth Doctor The Twelfth Doctor Thijarian Witness Think Twice Throes of Chaos Truth or Consequences Twice Upon a Time Vineglimmer Snarl Waterlogged Grove Wreck and Rebuild Yasmin Khan Masters Of Evil Finally, we've got Masters of Evil, a deck full of the biggest threats in all of time and space

I think that will be a ton of fun
In 2007, the Two-Headed Giant format was giving competitive Magic a goculminating in a Pro Tour defined by a draft strategyand there you could help ramp your other head to go bigger or faster