The benefits of investing in dividend stocks can feel modest when the major market indexes are notching all-time highs. But the passive income they provide can be an excellent supplement to your finances no matter what equity prices are doing.

Warren Buffett's safest passive income stocks are perfect for baby boomers looking to supplement Social Security or pension payments.

A high-yield ETF invests only in securities that pay distributions, but depending on the kind of fund, it may invest in stocks, bonds or even preferred stock to generate income. The fund’s strategy will list the types of securities that it invests in and the general approach it takes.

Oil stocks can be excellent sources of passive income for investors who can stomach the volatility of the cyclical energy sector. And with oil prices down 9% or so in the last year, many oil and gas stocks have sold off even as broader indexes like the S&P 500 make new highs.