On the “My Connections” page, I'd love to see an option to add a folder (and sub-folders).

Currently, there are options for "Developer orgs", "Sandbox orgs", "Production orgs", and "Scratch orgs".

If you are running more than one entity, having the sandboxes related to a single entity inside of a folder would be more user-friendly than having multiple dev/sandbox orgs inside the same folder.

For example, if I'm managing deployments for "ABC Company", "XYZ Company", and "LMNOP Company", and each has multiple sandboxes, it would be really convenient to be able to separate out their various sandboxes more effectively, into their own company folders, rather than all grouped inside of the same "Sandbox orgs" folder.

Custom user folders:

-  External Clients
    -  ABC Company
        -  Sandboxes
        -  Production org
    -  XYZ Company
        -  Sandboxes
        -  Training org
        -  Production org