Best index funds to invest in for August 2022 Invesco QQQ Trust ETF. Vanguard S&P 500 ETF. SPDR S&P 500 ETF Trust. Vanguard Russell 2000 ETF. iShares Core S&P 500 ETF. Schwab S&P 500 Index Fund. Vanguard Total Stock Market ETF. SPDR Dow Jones Industrial Average ETF Trust.