Treasure Hunter

Gain an additional 50 gold the next time you collect a Bounty Hunter stack. Increase the gold gained by 20 gold for each Bounty Hunter stack, up to 130 gold. Bounty Hunter stacks are earned the first time you get a takedown on each enemy champion.

Tree

Domination

Row

Row 3

In short

Unique takedowns grant additional gold the first time they are collected.

Patch

16.16.1