At the beginning of combat on your turn, if you've spent at least five mana to cast spells this turn, creatures you control get +1/+1 and gain trample until end of turn.

At the beginning of your end step, you gain 1 life.
Whitecliff Guardian gets +0/+1 for each 1 life you have above your starting life total.

Whenever a creature entering the battlefield under your control causes an ability of a permanent you control to trigger, draw a card. This ability triggers only once each turn.

When Widowed Maiden enters, return target creature card from your graveyard to your hand.
Spellcharge 3

Choose creature or land. Reveal the top four cards of your library. Put all cards of the chosen type revealed this way into your hand and the rest into your graveyard.

Tap up to one target creature. Creatures you don't control don't untap during their controllers' next untap step.
Flashback {4}{U}

Once each turn, when one or more cards leave your graveyard, you may have each opponent lose 1 life and you gain 1 life.
{2}{B}, Exile Writheling from your graveyard: Exile target card in a graveyard. You draw a card and you lose 1 life. Activate only as a sorcery.

Flash
{2}{B}, Discard Zyxthax Apex: Each opponent loses 3 life and you gain 3 life.
{6}{B}{B}: Return Zyxthax Apex from your graveyard to the battlefield tapped with a finality counter on it.