Infinite card drawNear-infinite lifegainNear-infinite lifegain triggersInfinite draw triggersNear-infinite +1/+1 counters on a creature
How it works
Gain life.
Fathom Mage triggers, putting a +1/+1 counter on itself
Fathom Mage triggers, causing you to draw a card.
Sheoldred triggers, causing you to gain 2 life.
Repeat from step 2.
By enchanting Fathom Mage with Sunbond, you turn every instance of card draw directly into a massive surge of +1/+1 counters. Once Sheoldred, the Apocalypse is on the field, the lifegain from drawing a card triggers Sunbond all over again to push another counter onto Fathom Mage. This instantly cascades back into Fathom Mage's own draw trigger, keeping the loop spinning endlessly to net you infinite cards, near-infinite life, and an arbitrarily huge Fathom Mage.