What you can respond to is effects that cause a coin flip to happen in the first place
Battle - Siege Battle (CTRL to add secondary) Creature Barrowgoyf Deathtouch, lifelink Barrowgoyf's power is equal to the number of card types among cards in all graveyards and its toughness is equal to that number plus 1
On the topic of board sweeps, there is one minion that outclasses the rest: Death Dealer
Kodama of the West Tree, for example, grants modified creatures trample and also allows you to grab a land from your deck and put it into play when a modified creature you control does combat damage to a player
Each deck has a 100-card deck, 4 foil legendary commander cards, 10 double-sided tokens and more
A card for this character was always going to care about spiders or heroes in some way, and card draw is the best way to do that