Unlike IPv4, an IPv6 address often has the variable information in the middle, while the last 64 bits may be constant and very closely connected to the user's computer (see https://en.wikipedia.org/wiki/IPv6_address#Address_formats).
It would be useful and effective to search for IPs/users by giving the constant end of the address. For example, *:742C:7B3F:FABC:E123
This is just the opposite of a /64 request.
Also possible in the format /-64 to simplify parsing.
Advanced level: combination of /+ and /- mask to search for the middle part. I think this request is uninteresting for IPv4.