Sanctuary Warden is a card Im pretty interested in running in a deck like Shalai, Voice of Plenty, where generated +1/+1 counters can be turned into card draw and chump blockers, while shield counters can do the most work under a blanket of hexproof
Counter target spell that targets you
If you do, this creature gets +X/+0 until end of turn and deals X damage to the player or planeswalker it's attacking
A 7/6 with trample also wont have too much trouble doing some combat damage, especially with haste
The only downside to this spell is that it exiles itself once it resolves, (un)luckily making sure that it cannot be looped and recurred, but this isn't much of a downside at all with a card this versatile
2, which contains one card determined by the odds below