Phyrexian Metamorph Infinite Life

Leonin Relic-Warder will play a huge part in this combo, because of his interactions with other cards.

Phyrexian Metamorph will be used to infinitely bounce the Loxodon Relic-Warder, by copying itself when it comes in, and because it's an artifact, you can bounce it infinitely.

And then Soul warden comes in (you can also use Soul's Attendant, which does the same thing). With the infinite bouncing combo involving the Relic-Warder and the Metamorph, the Relic-Warder bounces infinitely, and gives you infinite life through the Soul Warden.