If all costs are removed, Darius ult. An spammable overpowered damage nuke even without your target dying.
Lux's Lazor, Trynd's RAAAGGGEEE!=never dead
Counter to no CD Trynd's ulti would be no mana/energy cost hard CC. This would mean Lee sin's ultimate & Riven's W.
Thus, I would probably choose Lee sin's R.
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