Deal combat damage to an opponent using Etrata, triggering its ability.
Holding priority, activate Lithoform Engine and Strionic Resonator by paying {4} and tapping them, copying Etrata's trigger twice.
Resolve all Etrata triggers, exiling three creatures an opponent controls and putting hit counters on them, and then causing that opponent to lose the game.

Target opponent loses the game

Etrata, the Silencer

Lithoform Engine

Strionic Resonator

Deal combat damage to an opponent using Etrata, triggering its ability twice due to Roaming Throne.
Holding priority, activate Strionic Resonator by paying {2} and tapping it, copying either of Etrata's triggers.
Resolve all Etrata triggers, exiling three creatures an opponent controls and putting hit counters on them, and then causing that opponent to lose the game.

Roaming Throne

Deal combat damage to an opponent using Etrata, triggering its ability.
Holding priority, activate Gogo by paying {4} and tapping it, copying Etrata's trigger twice.
Resolve all Etrata triggers, exiling three creatures an opponent controls and putting hit counters on them, and then causing that opponent to lose the game.

Gogo, Master of Mimicry

Cast Echoing Equation by paying {3}{U}{U}, causing each other creature you control to become a nonlegendary copy of Etrata.
Deal combat damage to an opponent with Etrata and two other creatures you control.
Etrata and the two creatures trigger.
Resolve the first Etrata trigger, exiling a nontoken creature the opponent controls with a hit counter on it, and shuffle Etrata into your library.
Repeat step 4 one additional time.
Resolve the last Etrata trigger, exiling a nontoken creature the opponent controls with a hit counter on it, shuffle Etrata into your library, and cause the opponent to lose the game.

Augmenter Pugilist // Echoing Equation

Declare Etrata as an attacker, attacking an opponent that owns at least two cards in exile with hit counters on them.
Etrata's myriad ability triggers, creating four copies of it attacking each other opponent.
Deal combat damage with each Etrata, triggering their abilities.
Resolve the first Etrata ability, causing the opponent dealt damage by it to exile a creature they control with a hit counter on it, and lose the game if they have at least three cards in exile with hit counters on them.
Repeat step 4  for each remaining trigger.

Combos with "Etrata, the Silencer"