Cast Dismantle by paying {2}{R}, destroying Eternity Vessel, and putting a number of charge counters on Dragonspark Reactor equal to the number Eternity Vessel had.
Activate Dragonspark Reactor by paying {4} and sacrificing it, dealing damage equal to the number of charge counters on it to an opponent and up to one target creature.
The opponent loses the game due to having 0 or less life.

Near-infinite damage to one opponent

Target opponent loses the game

Eternity Vessel

Dragonspark Reactor

Dismantle

Cast Fate Trasnfer by paying {1}{U/B}, moving all counters from Eternity Vessel onto Dragonspark Reactor.
Activate Dragonspark Reactor by paying {4} and sacrificing it, dealing damage equal to the number of charge counters on it to an opponent and up to one target creature.
The opponent loses the game due to having 0 or less life.

Fate Transfer

March of the Machines

Activate Karn twice by paying {2}, causing Eternity Vessel and Dragonspark Reactor to become artifact creatures until end of turn.
Cast Fate Trasnfer by paying {1}{U/B}, moving all counters from Eternity Vessel onto Dragonspark Reactor.
Activate Dragonspark Reactor by paying {4} and sacrificing it, dealing damage equal to the number of charge counters on it to an opponent and up to one target creature.
The opponent loses the game due to having 0 or less life.

Karn, Silver Golem

Cast Dragonspark Reactor by paying {1}{R}.
Dragonspark Reactor triggers, putting a charge counter on itself.
All Will Be One triggers, dealing 1 damage to an opponent.
Malcolm triggers, creating a Treasure token.
Repeat from step 2.

Infinite charge counters on a permanent

Infinite colored mana

Infinite damage

Infinite Treasure tokens

All Will Be One

Malcolm, Keen-Eyed Navigator

Maskwood Nexus

Opalescence

Activate Xavier Sal by tapping it and removing a counter from a permanent you control, creating a copy of an artifact creature token you control.
When the creature token enters the battlefield, Intruder Alarm and Dragonspark Reactor trigger.
Resolve the Intruder Alarm trigger, untapping all creatures.
Resolve the Dragonspark Reactor trigger, putting a counter on it.
Repeat.

Combos with "Dragonspark Reactor"