Spy Combo wants to fill its graveyard and reanimate with Dread Return off Balustrade Spy mill and Lotleth Giant's undergrowth trigger, so Faerie Macabre's discard-to-exile ability is a key answer, stripping their graveyard to blank Dread Return targets and reduce Lotleth Giant damage. Stream of Thought actively mills your own library and is irrelevant filler here, so trim it for the Macabres. Your Fog suite remains excellent since their clock relies on building a wide board over several turns, giving you time to find answers. Keep the rest of the deck intact since none of their cards are red or artifact-based enough to justify other sideboard cards.