Value engine/synergy deck featuring Runes. Cost reduction (Runeforge Champion/Transcendent Envoy/Birgi, God of Storytelling) combined with card draw (Setessan Champion/Harnfel, Horn of Bounty) lets us play Runes cheaply (free if we have two cost reduction), letting us draw our entire deck.

When mulliganing, card advantage pieces are king. Generally only keep hands with Enigmatic Incarnation, Setessan Champion, or Runeforge Champion (or multiple pieces of removal against aggressive/combo decks) and 2-5 lands.

Against aggressive decks, bide time with removal and lifelink (Rune of Sustenance) until we assemble our synergy pieces and explode.

Against grindy decks, play runes onto lands so that they don't get fizzled by removal. Then they can be sacrificed later to Enigmatic Incarnation.

But the power of this deck isn't the combo, but rather that any individual combo piece is still strong on its own: 

Setessan Champion alone: Runes draw 2 cards and pump +1/+1

Harnfel, Horn of Bounty alone: Runes essentially scry 1, draw 2 (bc if the first draw isn't rune, you can discard to look at 2 more)

Harnfel, Horn of Bounty/Setessan Champion + Runeforge Champion/Transcendent Envoy/Birgi, God of Storytelling: same thing but runes costs (1) each

Harnfel, Horn of Bounty/Setessan Champion + Runeforge Champion+ Transcendent Envoy/Birgi, God of Storytelling: Runes are (0): draw 2

Harnfel, Horn of Bounty + Setessan Champion + Runeforge Champion + Transcendent Envoy/Birgi, God of Storytelling: Runes are (0): scry 1, draw 3, which probably draws the whole deck

Enigmatic Incarnation turns runes into our choice of any 3-drop creature, which includes every combo piece! Or against grindy deck, it can just make a 2/3 (Runeforge Champion) + draw a card every turn.

Enigmatic Incarnation sacrificing Rune to tutor Storm Herald draws a ton of cards (and can get a big hit). Note that the reanimated Runes don't get sacrificed until the next end step so they'll be around for blocking and we can even sac one of them to Enigmatic Incarnation again!