As you already know, the Roles page on Office 365 administration portal (https://admin.microsoft.com/) allows you to manage Office 365 roles assigned to your users.
Well, you can now define your favorites administration roles (aka the one you use/manage the most) to filter the available roles to only those ones.
To set an administration role as Favourites, logon to your Office 365 administration portal (ensure you are using the new admin center ) and reach out to the Roles page
Then browse the roles list and hit the Star shown on the right side to set it as favorites
Once you have set one or more favorites, you can use the Favorites filter