An exchange traded fund (ETF) is a type of security that tracks an index, sector, commodity, or other asset, but which can be purchased or sold on a stock exchange the same as a regular stock.
The frequently track an index like the Dow Jones, S&P 500 or Nasdaq, but may also track sectors, e.g. energy (XLE), financial services (XLF), or comodities.

US News ETF Rankings %
ETF Symbol Return
6 mos
SPDR S&P 500 (SPY) 16.1% 34.1%
Nasdaq-100 (QQQ) 14.2% 37.9%
iShares Core High Dividend (HDV) 12.0%
Schwab U.S. Small-Cap (SCHA) 10.6%
JPMorgan US Momentum Factor (Large cap Growth) JMOM 11.4% 33.6%
SPDR® S&P 400 Mid Cap Growth MDYG 9.0%
SPDR® S&P 600 Small Cap Growth SLYG 10.8%
Vanguard Growth (VUG) 14.8% 37.4%
Vanguard Russell 1000 Value (Large Value) VONV 16.1% 34.0%
iShares Core US REIT USRT 31.0% 35.0%
JPM client fund 17.3% 46.1%
MSCI World URTH 13.5% 31.7%
Note Value funds outpaced growth in Q1 2021, but Growth took the lead back in Q2.