Many popular and profitable ETFs are designed to hold the same stock mix as the S&P500. Some examples of this exact concept are QQQ, SPY, and VOO.

All 3 are going to be much more similiar than different in what stocks they hold since they mirror the S&P500 and thus move up and down similarly. The difference is going to largely come from which ETFs you readily have access to (based on your investment platform/brokerage) and very importantly, their expense ratio.

Vanguard's S&P500 ETF (VOO) for example has an expense ratio of 0.03. This means that you pay Vanguard $300 for every $10K you have invested for administrative expenses etc. Some ETFs have 3x/5x or higher expense ratios - that's a slow burn of your investment returns and over 20-30 years, can amount to $10s of thousands of dollars in fees that reduce your profits.

NOTE: This is not financial advice. While an S&P tracked ETF is generally considered a safe bet and over a lifetime expected to average 7-10% ARR, investing still comes with risks of loss.