We are already seeing clusters of digital currencies that seem to address a specific industry or share a similar approach to how to implement a digital currency.
For example, we have POS (Proof of Work), POS (Proof of Stake) and POC (Proof of Capacity) coins. We have coins that enable marketplaces of storage (like STORJ and Sia), while others are targeted at creating marketplaces for computing power (like Golem and iEx.ec), and so on. And of course we have Smart Contracts, Value Stores and coins that want to replace fiat in everyday transactions.
If would be very useful for analysis if we had indexes that grouped coins based on industry or technology used or even market cap (top, mid, low) and if we could see how the Storage Index or the DigitalContracts Index are doing over time or compare the trends between the POS and POW indexes or how the Top20 Index is performing over time.