Keen Sense For only one mana, [c]Keen Sense[/c] can draw you many cards over the course of a single game, but only if you can sneak the enchanted creature past your opponents defenses
Its an enters-the-battlefield effect, so itll only happen once, but sticking this 4/4 Orzhov flier to an empty field after it destroys every other creature cant be that bad
This helps to generate a large battlefield of creatures so that you'll always have blockers available to fend off any attackers
Sliver Legion is especially powerful since its effect scales off of the number of slivers on the battlefield, and this increase becomes exponential once there are multiple Sliver Legions
In the case of the former, you can even sacrifice Boromir in a key moment if you know that someone is holding free interaction that can stop someone else from winning the game
They cost three for a Temur 1/2 with ward 1 to protect a bit