Do you have room in your portfolio for some exchange traded funds (ETFs)?

If you do, it could be worth checking out the four ASX ETFs listed below that are highly rated. Here's what you need to know about them:

BetaShares S&P/ASX Australian Technology ETF (ASX: ATEC)

The first ASX ETF that could be a buy is the BetaShares S&P/ASX Australian Technology ETF.

It provides investors with access to leading ASX companies in a range of tech-related market segments such as information technology, consumer electronics, online retail and medical technology. This includes Xero Ltd (ASX: XRO) and Pro Medicus Limited (ASX: PME).

This ETF was recently named as one to buy by the team at Betashares. The fund manager commented: "With the nascent adoption of AI, cloud computing, big data, automation, and the internet of things, there's a good chance that the next decade's major winners will come from the tech sector. Despite Australia's sharemarket skewing heavily towards financials and resources, investors can gain direct exposure to Aussie tech stocks via ATEC."

Betashares Australian Top 20 Equity Yield Maximiser Fund (ASX: YMAX)

If you are interested in generating an income from the share market, then the Betashares Australian Top 20 Equity Yield Maximiser Fund could be a great option.

It aims to generate quarterly income through an equity income investment strategy over a portfolio of the 20 largest blue-chip shares listed on the ASX.

Betashares recently recommended the ETF as an option to counter falling dividend yields. It said: "Betashares' range of Yield Maximiser funds use a covered call strategy to offer additional income over and above dividends generated by the portfolio. This approach takes a two-pronged strategy: earning dividends from the underlying stocks and generating income from writing call options on those shares."

At present, the ETF trades with a trailing 12-month dividend yield of 6.9%.

Vanguard All-World ex-U.S. Shares Index ETF (ASX: VEU)

A third ASX ETF for investors to look at is the Vanguard All-World ex-U.S. Shares Index ETF.

It provides investors with access to ~3,500 companies that are listed in developed and emerging markets across the world but excluding the United States.

Vanguard notes that this makes it a convenient way to get broad exposure across developed and emerging non-U.S. equity markets around the world.

Among the ASX ETF's holdings are companies such as HSBC Holdings, LVMH Moet Hennessy Louis Vuitton, Samsung, and Taiwan Semiconductor.

Vanguard MSCI Index International Shares ETF (ASX: VGS)

Finally, the Vanguard MSCI Index International Shares ETF could be a great option if you want your global exposure to include US-based stocks.

It provides investors with access to a large number of listed companies from major developed countries.

At present, the fund has approximately 1,500 holdings, which makes it a great way to diversify a portfolio and provide it with exposure to global economic growth.

Its holdings include many of those in the Vanguard All-World ex-U.S. Shares Index ETF as well as the likes of Apple (NASDAQ: AAPL), Nvidia (NASDAQ: NVDA), and Eli Lilly & Co (NYSE: LLY).