What I mean is: Are there other markets.

I see 3 markets:

    Stock markets
    Domain markets
    Crypto exchanges

ETFs are traded on the stock markets.

I wonder if those 3 markets are somehow special or if there are more.

With the stock market, you can pick a company and invest in it. With Domain markets, you can invest in a single domain you believe in. Same for crypto markets where you can invest in a single crypto currency.

With ETFs you can't invest in a specific thing. You are investing in some category.