Which is the best aggressive investment option for someone with the horizon of 30 years - mutual funds, ETFs or index funds.
I would say mutual funds as compared to ETF or index fund. Both ETF and index fund are almost the same with the difference being ETFs are traded on the market. Index funds are operated as open-ended funds and so are ETFs which are mounted on an index fund. Coming to mutual funds, equity mutual fund is the key. For a higher return, a mix of small cap, mid cap and a multi-cap funds will do.
However, investing is one part and sticking through investments plan over the next 30 years is a different story. You shouldn't get swayed away by the kind of volatility that exists in these funds. So configure yourself psychologically and then start your investment plan in these fund categories. In this long a time horizon you will get at least two to three market cycles where you might regret your decision, but being regular will help and you will realise the benefit of it towards the end.