Prisoner's Dilemma Groundhog Day
This is a Jeskai deck based around the Flashback keyword (and some other related cast-from-graveyard keywords)  to cast, create multiple copies, recur, and even potentially create infinite  loops. to burn down or mill out opponents, as well as pit them against each other. Also, since Sevinne prevents all damage that would be done to it and it's fun to use all parts of the buffalo, there is some quality Pariah nonsense.

Primary Win Conditions
• Cast, copy, and flashback Prisoner's Dilemma with various spell copy tools, triggering Sevinne, the Chronoclasm for more copies (Harmonic Prodigy and Veyran, Voice of Duality will copy triggers)
• Generate multiple tokens from any of a variety of sources and copy Prisoner's Dilemma multiple times with either Surge to Victory or Complete the Circuit (Harmonic Prodigy copies Surge triggers for creatures with the correct types)
• Additional mass copy targets are Acidic Soil and Price of Progress with either life gain from Soulfire Grand Master or Heartflame Duelist // Heartflame Slash, or a Pariah effect on Sevinne or Brash Taunter; as well as Space-Time Anomaly to mill people out; and Ensnared by the Mara for huge value and lots of cast triggers to make tokens.

Alternate Win Conditions
• Infinite damage loop with Ral, Storm Conduit by creating infinite copies of Increasing Vengeance or Refuse // Cooperate with Sevinne's triggered ability (the flashback loop)
• Infinite damage loop with Brash Taunter, Arcbond, and either Pariah or Gideon's Sacrifice
• Generating infinite red mana by looping Mana Geyser through Soulfire Grand Master's buyback ability, and then infinitely looping Acidic Soil or Price of Progress
*All infinite combos require three cards, at least one on-board permanent that can be removed to stop them, and a hefty mana investment to execute in one turn; which I feel makes them bracket 3 appropriate. They are also no otherwise-dead combo cards, they all have additional deck utility and are useful in their own right.

Notable Interactions
• Recruiter of the Guard can find Soulfire Grand Master/Hearthflame/Brash Taunter for combo, token generators, Sand Scout to ramp, and trigger doubler creatures depending on what is needed
• Ensnared by the Mara can often generate multiple token creatures from additional free casts if opponents opt to not take burn damage
• Space-Time Anomaly can be used to mill about half your library to find flashback cards, and is then in prime position to be copied with Surge to Victory.
• Pariah and Gideon's sacrifice both double as protection with Sevinne if needed
• Life gain from giving instants or sorceries lifelink happens during the resolution of the spell before state based actions can be checked, so you cannot kill yourself with the damage from symmetrical burn spells with these effects in place provided players can gain life normally.