Grixis Affinity wins through card advantage engines like Ichor Wellspring and Reckoner's Bargain fueling large threats like Myr Enforcer and Utorm Monitor, backed by Galvanic Blast for removal. Dust to Dust is your most impactful sideboard card, efficiently destroying key artifacts like Ichor Wellspring and Myr Enforcer at two-for-one value. The additional Suffocating Fumes gives you more sweeper coverage against their artifact creatures, and the extra Mukotai Ambusher provides a resilient threat that can recur from the graveyard to grind them out. Prismatic Strands loses significant value since Grixis Affinity rarely attacks with a wide white-creature board, and Oroku Saki is too slow against their explosive starts. Your Refurbished Familiar and Glint Hawk engine still generates card advantage, so focus on disrupting their artifact synergies early while keeping up removal for their big threats.