Sideboard options:

Thorn of Amethyst (2, Artifact, Noncreature spells cost 1 more to cast)
Guttural Response (G/R, Instant, Counter target blue instant spell)
Dolmen Gate (2, Artifact, Prevent all combat damage that would be dealt to attacking creatures you control)
Bow of Nylea (1 GG, Legendary Enchantment Artifact ,Attacking creatures you control have deathtouch.
1G, Tap: Choose one — Put a +1/+1 counter on target creature; or Bow of Nylea deals 2 damage to target creature with flying; or you gain 3 life; or put up to four target cards from your graveyard on the bottom of your library in any order )
Tower Defense - (1G, Instant, Creatures you control get +0/+5 and gain reach until end of turn)

Main Deck Options:

Nylea, God of the Hunt
Polukranos, World Eater