Haldir, Lórien Lieutenant 

Legendary Creature — Elf Soldier
Haldir enters with X +1/+1 counters on it.
Vigilance
{5}{G}: Until end of turn, other Elves you control gain vigilance and get +1/+1 for each +1/+1 counter on Haldir.
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Cards that do something similar expected a card that isn't here?
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Prime Speaker Zegana 85%
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Slurrk, All-Ingesting 84%
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"this card enters with five +1/+1 counters on it."
+1 more matching line
Polukranos, Unchained 81%
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"this card enters with six +1/+1 counters on it. It escapes with twelve +1/+1 counters on it instead."
+1 more matching line