This is a near-mirror against 4c HollowOne, so Surgical Extraction is excellent at exiling a discarded Hollow One, Vengevine, or key card from their graveyard to deny them a cheap castable threat or a Vengevine return. Meltdown at X=5 can blow out their Hollow One if it's been discounted to be cast for cheap, since Hollow One is an artifact creature and Meltdown destroys artifacts up to the chosen X value. Ox of Agonas is symmetrical value that doesn't provide an edge in the mirror and can be a liability if they have a faster clock, so it comes out. Nethergoyf is a fine racer here but Surgical Extraction and Meltdown provide more proactive disruption of their specific game plan, so a couple copies are trimmed.