There are roughly 2,400 exchange-traded products listed in the U.S., including both exchange-traded funds and exchange-traded notes. Underscoring what a wild ride equity markets have been on this year, fewer than 80 of those products are up 30% or more year to date and when leveraged funds are removed from the equation, the universe dwindles even further.

With the S&P 500 up 16.65%, it might be reasonable to expect more niche and nuanced ETFs would be in the 30% club. Alas, the list is small, but still, chock full of opportunity.

Here, we'll examine three ETFs that are up at least 30% this year with the potential to keep adding to those gains into year-end and beyond.

Pacer Benchmark Industrial Real Estate SCTR ETF (INDS)

YTD Gain: 34.9%

The Pacer Benchmark Industrial Real Estate SCTR ETF INDS has been on an indomitable run that has the fund outperforming the largest real estate ETF by about 1,000 basis points this year.

INDS' underlying index invests “invests “in industrial REITs that are part of the e-commerce distribution and logistics networks along with self-storage facilities,” according to Pacer.

Reminders are regularly popping up that INDS has the goods over traditional real estate ETFs. For example, mall vacancies are rising and Forever 21, as just one example, recently went bankrupt. Translation: e-commerce is disrupting brick-and-mortar and INDS puts investors front and center to the real estate needs of online retailers.

Investors are likely to get another reminder of this when holiday shopping numbers start trickling in, meaning INDS has some tailwinds heading into 2020.

ALPS Clean Energy ETF (ACES)

YTD Gain: 35.16%

Several of the ETFs in the 30% are club are clean energy funds and one of the leaders of the pack is the ALPS Clean Energy ETF (CBOE: ACES). One of the more compelling traits with ACES is that it doesn't confine investors to one corner of the alternative energy space. Rather, the fund offers exposure to seven clean energy themes, a hefty amount compared to rival funds.

Declining production costs and increased adoption of green energy at the corporate level are among the factor boding well for ACES.

The move to clean energy “is disruptive to traditional sources of energy, but it also presents a compelling and long-lasting investment opportunity for the companies and industries positioned for the change," according to ALPS.

Global X Greece ETF (GREK)

YTD Gain: 31.45%

Here's all one needs to know about how far Greece has come: the once financially downtrodden nation that lost its developed market status as a result of a debt crisis on Wednesday issued negative-yielding debt.

While there are still risks in the Greek economy, negative-yielding indicates the country has come a long way from the days in 2012 when it was widely speculated that the country was on the cusp of being booted from the Eurozone.

The risk with the Global X Greece ETF GREK is that the country's equity market is reflecting a highly ebullient tone while not accounting for vulnerabilities that could be realized if the European economy further slows.