With the addition of SoS , I feel this should be adressed. Instead of adding new cards though, I think the easiest way would be to modify existing cards.
Currently, cards that allow healing are....
-Vamp Dagger, Vamp, Drain Life
-Antimatter
-Black Hole
-Heal, Feral Bond
-Holy Light
Changes I could see-
Drain Life-Heal your opponent if you are targeted with it
Heal-Become target-able.
This is just a quick list, so im probably missing something, and theres probably more creative ways these existing cards can be modified to have anti synergy with SoS, but im sleepy, so I figured Id create the topic and see what the community has to say