Thoughtseize is premium here, stripping their Doomsday or a key piece before they can assemble the combo. Mindbreak Trap exiles multiple targeted spells at once (often free if they've cast three-plus spells that turn), making it a strong catch-all answer to a resolved Doomsday pile or a Thassa's Oracle attempt even through Force of Will/Daze protection. Faerie Macabre and Surgical Extraction can proactively strip Thassa's Oracle or a key piece from their hand/graveyard before they combo off, and Surgical Extraction can also remove the Doomsday pile itself if we see it. We cut slow equipment that does nothing to interact with a combo kill.