A little bit of healing goes a
very long way in a controlbow like Antagonbow. Between lots of CC and Fog Shield, it really lets you survive alternate damage sources well, such as Poison.
However, the usual choice would be Sanctuary. Antagonbow uses no
and Sanc protects against Black Hole and Nightmare. That does matter.
Nevertheless, the point stands that Antagonbow is a rushy controlbow, and that 30 cards optimizes draws. Normally I swap one Momentum for Sanc, but if you're going to use it against Bronze (which is your best bet for rares with your card base), I wouldn't do that. There are tons of Monoaethers in Bronze, so you definitely need many ways around Dimensional Shields.