If were ready to switch gears to start winning the game, we can find anything from Sigil of the Empty Throne to our planeswalker of choice to something like Archangel Avacyn or Ulamog, the Ceaseless Hunger
At some video game tournaments using the Tag Force series of games, Match winners have been allowed (due to the game not marking them as Forbidden) since the game mechanics enforce the rule that surrendering is only allowed during the player's turn, and only starting from the 10th turn of the Duel.
This is another general miss for Vintage Cube, but the more your Cubes gameplay centers on combat, the more appealing The Wandering Emperor becomes
Kashtira Riseheart , Scareclaw Kashtira and Kashtiratheosis are extenders that aids in making Rank 7 plays
You can also keep the booster box sealed as an investment
The other route leans into bounce effects like Crystal Shard or blink engines such as Thassa, Deep-Dwelling, which deliberately trigger the leave-the-battlefield ability to gain extra turns