Anti
Landing Ana's Biotic Grenade or similar anti-heal on a key enemy to zero out their healing economy.
The single biggest swing element for ending a sustain war unilaterally: a target that gets Anti'd has healing fully nullified, so their effective HP collapses. A good Anti is one layered onto focus or an ult to turn it into a confirmed kill; thrown on its own it just gets stripped by Suzu, Fade, or damage reduction. Whether the Anti gets through or gets denied directly decides brawl matchups. It's the ability in Ana's entire CD kit that moves games the most.
When the enemy tank is under focus and Suzu is down. When you want full healing denial locked in before a Wombo Combo. Shutting down the enemy supports before Nano Blade.
The enemy instantly cleanses with Suzu or Fade and the Anti does nothing. Getting CC'd right after throwing it and missing the confirmed kill. Throwing it in meaningless neutral and wasting the CD.
Resource Trade
Spending a minor cooldown to force a major defensive one, netting an advantage for the real fight.
Wombo Combo
Stacking multiple ultimates within one second to bypass defensive cooldowns and wipe the team.
Bait Ult
Forcing the enemy to spend an ultimate on empty space or a low-value target.
Sustain War
A standoff where both teams' healing output exceeds incoming damage, preventing kills and prolonging the fight until the balance breaks.