Many investors look to exchange-traded funds, or ETFs, as a straightforward tool to align their portfolios with simple goals without extra cost or complexity. Right now, the ETF universe includes many low-cost, diversified dividend funds that can really take your income investing strategy to the next level. While some folks may like to chase high dividend yields, picking individual stocks can be time-consuming – and if you don't build your holdings with diversification in mind, you could actually create unintended risks. The following nine dividend ETFs offer slightly different ways to invest for income in a diversified and low-stress way. They all also deliver better payouts than the S&P 500 index's (.SPX) current 1.34% yield, but they approach dividend investing in various ways to fit your unique portfolio.

Vanguard Dividend Appreciation ETF

The best dividend ETF if you're measuring simply by size is VIG (VIG), Vanguard's flagship equity income fund that commands roughly $70 billion in assets under management at present. As is typical of Vanguard's low-cost index funds, VIG is dirt-cheap at just 0.06% in annual expenses, or a mere $6 on every $10,000 you invest. The trade-off, however, is that this fund isn't particularly sophisticated; it holds about 250 top dividend stocks in the U.S., led by megabank JPMorgan Chase & Co. (JPM) and tech giant Microsoft Corp. (MSFT), with a median market capitalization of $167 billion. If you don't mind this bias toward larger stocks you may have exposure to elsewhere or the relatively modest yield, VIG offers low-risk investors a cheap, one-stop spot for dividend stocks.

Current yield: 1.5%

SPDR S&P Dividend ETF

Though perhaps not as big as VIG, the $20 billion SDY fund (SDY) is another dividend ETF worth noting that is very popular. It has a more focused list of about 113 total holdings, led right now by energy giant Exxon Mobil Corp. (XOM) and telecom AT&T (T). Thanks in part to a focus on stocks that pay back shareholders generously instead of stocks like Microsoft that pay a nominal dividend of less than 1%, SDY offers considerably better income potential than the prior Vanguard fund. Just be aware that it's more expensive, with a 0.35% expense ratio.

Current yield: 2.52%

Schwab U.S. Dividend Equity ETF

Another leading dividend ETF worth a look is this Schwab fund (SCHD) that marries the affordability of Vanguard with the focused approach of the prior SPDR fund to get the best of both worlds. It, too, charges just 0.06% annually in fees but has a focused list of about 100 holdings that drive a yield that's almost twice that of the S&P 500 at present. The catch, however, is that SCHD achieves this yield by "overweighting" some names that pay more. Right now, top positions include names like drugmaker Merck & Co. (MRK) and Home Depot (HD) that pay more than the typical blue-chip stock – but because of this approach, 40% of SCHD's assets are in the top 10 positions alone. This may not be a deal breaker, but the approach is noteworthy before you dive into this dividend ETF.

Current yield: 2.72%

iShares Select Dividend ETF

Another big-time dividend ETF, this iShares offering (DVY) has $18 billion or so in assets. However, it begins the next grouping of funds on this list by taking a more qualitative approach to its components instead of just looking at big stocks that pay some form of dividend. Specifically, DVY layers on a screening methodology that, among other things, demands five years of consistent payouts to ensure reliability. The result is another fund with about 100 holdings and a yield similar to a few of the prior funds. The holdings here are much different, with Oklahoma-based natural gas firm Oneok (OKE) and tobacco giant Altria Group (MO) taking the top positions. Added to that, it boasts a generous yield with only 19% of assets in its top 10 holdings to show it prioritizes diversification, too.

Current yield: 2.99%

iShares Core Dividend Growth ETF

A slightly different approach is this sister iShares fund (DGRO) with $19 billion in assets that focuses not just on a track record of payments but the track record of those payments growing over those five years – and that the dividend isn't more than 75% of total earnings, and therefore likely to keep growing without breaking the bank. Perhaps surprisingly, this doesn't mean you're getting a tiny list, as DGRO includes a wider swath of the market with nearly 390 holdings instead of just focusing on a small list of popular blue-chip stocks like some other funds.

Current yield: 2.06%

ProShares S&P 500 Aristocrats

If you like consistency in your dividends, then take note of NOBL (NOBL) that focuses on "dividend aristocrats." This term refers to certain companies in the S&P 500 that have increased their dividend payouts for 25 consecutive years or more. That's an eternity on Wall Street, proving the components have a great pedigree as income stocks but also that they have consistent operational success to support this kind of commitment to profit-sharing with stockholders. To be clear, this doesn’t mean every payday is a huge one. As a result, other dividend ETFs on this list offer better yields. That said, the 65 picks that make up this fund do offer stability and consistency over the long haul.

Current yield: 1.93%

Global X SuperDividend ETF

Consistency is all well and good, but what about those dividend investors who just want to get paid as much as possible? Well, for them, this Global X "super dividend" fund (SDIV) should do the trick. Rather than focusing on the most mature or reliable income investments, SDIV instead prioritizes yield to generate a payout more than four times that of the typical S&P 500 stock. That reward does come with greater risk, of course, as the portfolio of stocks includes international names like small Chinese companies you have likely never heard of before. In fact, less than 30% are U.S. companies at present. There's strength in numbers, though, and the idea is that roughly 100 of these names will be diversified enough to prevent undue volatility if one or two of these lesser dividend stocks hits a snag. Just beware of the risk and international exposure you're taking on in this $1 billion fund.

Current yield: 6.65%

WisdomTree U.S. MidCap Dividend Fund

Another interesting way to pursue dividend stocks is this $3 billion WisdomTree fund (DON) that excludes the biggest and the smallest stocks to find midsize dividend payers. After all, if you have other blue-chip stock holdings, chances are you have exposure to many of the top positions in these other funds already. So why not add in this list of about 300 stocks held by DON that you may not already own? We're not talking obscure corporations, either, with top holdings including Rubbermaid container manufacturer Newell Brands (NWL) and wire payments provider Western Union Co. (WU). The yield is slightly better than the S&P 500, and this ETF won't have much overlap with large-cap index funds because of this focus on mid-cap stocks.

Current yield: 1.84%

Invesco S&P 500 High Dividend Low Volatility ETF

The $3 billion Invesco fund (SPHD) is unique in that it prioritizes both income as well as lower-volatility investments that should be more stable than their peers. The portfolio is focused on just 50 or so stocks that exhibit lower share price volatility over the last 12 months when compared with other stocks, resulting in a diverse group of companies that range from traditional large-cap income plays like tech giant IBM (IBM) to lesser-known medical office space provider Healthpeak Properties (PEAK). With a yield that's more than double the typical stock in the S&P 500 and a lower risk profile than this benchmark thanks to the focus on stable names, this is a quirky but potentially valuable dividend ETF worth a look.

Current yield: 3.85%