I too would like to add my +1 to this 6-year old feature request.
Here's an example: I have a lot of Salesforce (over 20) so it's helpful to only show me the relevant logins for the relevant domains. URL Rules handle this nicely when I go directly to my Salesforce URL (https://acmecorp.my.salesforce.com
). Things get hairy when I go to the global login pages. For Salesforce this is https://login.salesforce.com
for production logins, and https://test.salesforce.com
for sandbox logins. I'd love to set up my production domains as equivalent to login.salesforce.com and my sandbox domains as equivalent to test.salesforce.com instead of having to go through my whole list of logins.