Some decks want Chivalric Alliance and Tocasias Welcome, while others want Trouble in Pairs or Wheel of Fortune and Imposing Grandeur
In green, Tyvars Stand provides hexproof and indestructible for one mana, but it can also act as a finisher by pumping your creatures power for X mana, ensuring the card is never a dead draw
This means that by casting several spells, Hullbreaker Horror can be used to return several key cards to their owner's hand, setting opponents back to the Stone Age
The best options for this role are Brass Knuckles, Fireshrieker, and Grappling Hook
Moreover if you do the math, drawing many cards gives you card advantage and access to all other aspects of your deck more quickly, so you have greater chance to have access to more lands, ramp, removal, utility, creatures, combo pieces, even more card draw and any other strategy you may run in your deck