Wall Street was overall upbeat last week. Though concerns about the spread of the Delta variant of coronavirus worried investors, low rates boosted the demand for stock investments. The S&P 500, the Dow Jones and the Nasdaq Composite added about 1.96%, 1.08% and 2.84%, respectively, last week.Wall Street had a shaky start to the week due to a spike in U.S. COVID cases, which is a potential threat to economic reopening. The Dow Jones in fact had logged a 725-point loss on Jul 19,marking the worst day since October. The benchmark U.S. treasury yield fell to as low as 1.19% on Jul 19.However, investors shrugged off fears and again entered the market rally with full enthusiasm. The Dow Jones then enjoyed its strongest two-day (on Jul 20 and Jul 21) rally since March. The S&P 500 and the Nasdaq too were in fine fettle. Upbeat earnings also helped the markets to bounce back.The small-cap benchmark Russell 2000 Index saw the biggest rebound with a 1.7% gain. The 10-year yield too jumped back to 1.30% on Jul 23. Many of the stocks that were hit the hardest on Jul 19, on concerns about the COVID-19 Delta variant, rebounded in the days that followed. Airlines and cruise companies spearheaded the revival (read: Risk-On Sentiments Back: 5 ETFs Up At Least 7%).Against this backdrop, below we highlight a few ETF areas that were extremely gainful last week.Soft Commodities iPath Series B Bloomberg Coffee Subindex Total Return ETN JO – Up 18.9%iPatha.B Softs Subindex TR ETN JJS – Up 8.9%Agricultural commodity prices have jumped since last year due to a rise in Chinese imports and tightening inventories. Rising inflation is also helping agricultural commodity prices (read: 5 ETFs to Profit From Higher Food Prices).Consumer Discretionary Simplify Volt Pop Culture Disruption ETF VPOP – Up 11.1%Delta variant continues to be a major concern as the number of cases is rising in the world’s largest economy. As a result, the stay-at-home option of media and entertainment has been a winning one (read: 5 ETFs Worth Your Attention as Delta Variant Continues to Spread).The ETF VPOP is active. The Simplify Volt Pop Culture Disruption ETF seeks to concentrate in those few disruptive companies poised to dominate the new era of media and then enhance the concentrated exposures with options.Shipping Breakwave Dry Bulk Shipping ETF BDRY – Up 10.5%A global economic recovery has brightened the demand outlook for all vessel categories, leading to a spike in the shipping rates. This fund provides exposure to the dry bulk shipping market through a portfolio of near-dated freight futures contracts on dry bulk indices (read: Consumer Price Sees Biggest Jump in 13 Years: ETFs to Gain).Natural GasiPath.B Natural Gas Subindex ETN GAZ – Up 9.8%US Natural Gas Fund( UNG) – Up 9.7%Warmer-than-normal weather is expected to remain in most of the United States over the next 6-10 and 8-14 days and this will likely boost cooling demand. As a result, the demand for natural gas brightened up last week.Cloud & Cybersecurity Simplify Volt Cloud and Cybersecurity Disruption VCLO – Up 8.4%Renewed demand for stay-at-home stocks have boosted the lure for tech-related companies. This thematic investment product – VCLO – is actively managed and designed to concentrate on those few disruptive companies that are poised to dominate the new era of the cloud and then enhance the concentrated exposure with options. Time to Invest in Legal Marijuana If you’re looking for big gains, there couldn’t be a better time to get in on a young industry primed to skyrocket from $17.7 billion back in 2019 to an expected $73.6 billion by 2027. After a clean sweep of 6 election referendums in 5 states, pot is now legal in 36 states plus D.C. Federal legalization is expected soon and that could be a still greater bonanza for investors. Even before the latest wave of legalization, Zacks Investment Research has recommended pot stocks that have shot up as high as +285.9%. You’re invited to check out Zacks’ Marijuana Moneymakers: An Investor’s Guide. It features a timely Watch List of pot stocks and ETFs with exceptional growth potential.Today, Download Marijuana Moneymakers FREE >>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report iPath Series B Bloomberg Coffee Subindex Total Return ETN (JO): ETF Research Reports iPath Series B Bloomberg Natural Gas Subindex Total Return ETN (GAZ): ETF Research Reports United States Natural Gas ETF (UNG): ETF Research Reports iPath Series B Bloomberg Softs Subindex Total Return ETN (JJS): ETF Research Reports Breakwave Dry Bulk Shipping ETF (BDRY): ETF Research Reports Simplify Volt Pop Culture Disruption ETF (VPOP): ETF Research Reports Simplify Volt Cloud and Cybersecurity Disruption ETF (VCLO): ETF Research Reports To read this article on Zacks.com click here. Zacks Investment Research