The SPDR Gold Trust (GLD) garnered $2B in fresh AUM in August, the most of any ETF as gold put in its biggest bull move since January. The number 2 asset-gatherer was the Vanguard Emerging Markets ETF (VWO), but investors weren't performance-chasing there - the fund finished about flat for the month.
From other sites
ETF Screener: Search and filter by asset class, strategy, theme, performance, yield, and much more
ETF Performance: View ETF performance across key asset classes and investing themes
ETF Investing Guide: Learn how to build and manage a well-diversified, low cost ETF portfolio
ETF Selector: An explanation of how to select and use ETFs