There are literally thousands of exchange-traded funds (ETFs) available to investors covering broad swaths of the market and just about every sector, industry, investment style, and category within it.

ETFs truly simplify the process of putting together a broadly diversified portfolio with just a few different ETFs. Here are three ETFs that give you all the diversification and growth you need for retirement.

1. Vanguard Total Stock Market ETF

The Vanguard Total Stock Market ETF gives you pretty much all the diversification you need in one investment because this fund tracks the entire investable universe of stocks traded on the New York Stock Exchange and Nasdaq. It has more than 4,000 holdings, from the biggest mega caps to the smallest micro caps. But because it is market-cap weighted, large caps make up the bulk of the portfolio.

The three largest holdings are Apple, Microsoft, and Amazon -- with the top 10 holdings making up about 24% of the portfolio.

Over the past five- and 10-year periods through July 31, it has an average annual return of 12.1% and 13.4%, respectively. Year to date, it is down about 17% as of Aug. 31. This ETF trails the S&P 500 slightly year to date and over the past five and 10 years, but it beats the S&P 500 over the past 20-year period with an 8% average annual return as of Aug. 31. This better 20-year performance record is why I favor it over an S&P 500 index fund as a core investment. It also has a next-to-nothing 0.03% expense ratio.