Heartless Hidetsugu deals damage to each player equal to half that players life total, yourself included
(It's an artifact with " , , Sacrifice this token: You gain 3 life.") , Sacrifice this enchantment: Target opponent loses X life, where X is the amount of life you gained this turn
Otherwise legends have become so abundant that sacrificing one for a clutch counter wont be difficult, especially if they want to die or can come back on their own
On card advantage specifically
Stormanother "mistake" mechanicwas continually targeted by bannings even after the deck was essentially unplayable, and the only reason that makes sense is that Wizards simply wants to wipe the memory of the mechanic out of existence
+3/+0 doesnt help most creatures to survive combat, but its quite strong on evasive creatures, so the strength of this card is quite variable