I know that Codeforces have user finding tool, but I think it is not a really good tool to find users we don't know his or her whole id.

I really hope that Codeforces can upgrade this tool. The tool on AtCoder is a good model. Such as this page and this page on AtCoder. It allows us just provide some imformation and then it will give us all users meet the requirements.

With these tool which can allow us just provide some substring of the whole id we'd like to find, we can better find the users in Codeforsces.