What are the best Cryptocurrencies Index funds?

Could you elaborate on what the best Cryptocurrencies Index funds are, and why they stand out from the rest? I'm particularly interested in their performance over the last few years, their investment strategies, as well as any notable risks or advantages they may have. Do they focus on a specific set of cryptocurrencies or are they diversified? Are they suitable for long-term investors or more suited for those looking for short-term gains? Lastly, how do they compare to other traditional investment options in terms of risk and return? Thank you for your insights.