Unlimited Raise Dead

Unlimited Raise Dead: Infinite Ruin is the name of two phenomenon in which a non-stop loop generates essentially infinite beings.

Fate/hollow ataraxia
Avenger, granting the wish of Bazett Fraga McRemitz, loops a four day period over within a dream world, each time leaving behind a shade of himself. Over countless loops, this produces a countless number of shades.

Fate/Extra Last Encore
Both Rin Tohsaka and Rani VIII are declared the Floor Master of the sixth floor of the Moon Holy Grail War after they tie in battle and Chakravartin shuts down the war. Due to this factor, they begin to produce countless avatars that endlessly wage battle in an attempt to bring about a victor to the battle.