This year has been a challenging one for investors. The S&P 500 is down more than 21%. It could decline even further if we head into a recession. 

However, challenges bring opportunities. One of those is that dividend yields move in the opposite direction as stock prices. Because of that, this year's sell-off is providing income investors with the opportunity to lock in higher yields in some of the best dividend stocks.

Three elite dividend stocks that stand out as attractive long-term opportunities after selling off this year are Consolidated Edison (ED 0.64%), Federal Realty Investment Trust (FRT 0.71%), and Verizon (VZ -0.53%). 

The power to keep growing

Consolidated Edison's stock has declined by 13.5% this year. That has pushed the utility's dividend yield up to 3.6%, more than double the S&P 500's 1.7% dividend yield. 

What stands out most about Consolidated Edison is its elite dividend track record. The company delivered its 48th consecutive annual dividend increase earlier this year.

That's the longest period of consecutive annual increases of any utility in the S&P 500. It squarely puts Consolidated Edison in the elite class of Dividend Aristocrats, and now it's just a couple of years shy of the even more exclusive list of Dividend Kings. 

Consolidated Edison should be able to continue growing its dividend in the future. The company's dividend-payout ratio remains within its 60% to 70% target range, which gives it a nice cushion while allowing it to retain earnings to fund capital investments.

The company also has a solid investment-grade balance sheet. It's enhancing its financial flexibility by selling its clean-energy subsidiary for $6.8 billion. That will put it in an even better position to finance the $68 billion of investments it sees over the next decade, which should drive steady earnings growth.

Focusing on quality pays dividends

Federal Realty Investment Trust has lost more than a quarter of its value this year. That's driven the real estate investment trust's (REIT) dividend yield up to 4.2%. 

Federal Realty has delivered industry-leading consistency. It has increased its dividend for 55 straight years, the longest streak in the REIT sector. That easily puts it in the exclusive class of Dividend Kings. 

Federal Realty focuses on quality over quantity. It owns 105 shopping centers across nine major metro areas. It concentrates on owning high-quality shopping centers (primarily anchored by grocery stores) in the top suburban markets. That helps drive above-average rent growth.

Its location focus also allows the REIT to redevelop its shopping centers for the highest and best uses, including adding apartments, offices, and other property types that diversify and grow its revenue streams. Federal Realty also maintains a strong investment-grade balance sheet, giving it the financial flexibility to continue making investments that grow its rental revenue and dividend.

A cash flow machine

Shares of Verizon have tumbled 31% this year. That pushed the telecom-giant's dividend yield up to 6.9%

The company also has an elite dividend track record. It delivered its 16th consecutive annual dividend increase this year, the longest current streak in U.S. telecom industry.

Verizon should be able to continue growing its dividend in the future, as it generates an enormous amount of cash. The telecom giant produced $28.2 billion of free cash flow from operations during the first nine months of this year. It spent $15.8 billion on capital projects to maintain and expand its networks while paying $8.1 billion in dividends.

That enabled Verizon to produce $4.3 billion in excess cash to maintain its solid balance sheet. The company's heavy network investments should grow its free cash flow in the future. That should allow Verizon to continue paying a lucrative and growing dividend.

Great income opportunities these days

Consolidated Edison, Federal Realty, and Verizon have elite dividend track records. Despite that, all three have seen their share prices tumble this year, along with the broader market.

Because of that, investors can lock in even higher dividend yields. That combination of yield and elite growth makes them stand out as great options for those seeking passive income streams that should continue to withstand the test of time.