In Teams Manager, the number of teams you're able to view differs based on your role within your organization.
If you're an Admin and cannot see the desired teams, it could be because you're in a specific View that doesn't contain any teams. You can adjust the View in the top right corner of the Teams tab.
There's a chance that you're looking for Unmanaged Teams. These are teams that were created outside of Teams Manager and thus do not show up within the app until they're converted into Managed Teams.
If you've verified that none of these are the issue, click on the … button in the top right corner of Teams Manager and reload the app.
For regular users, the number one reason for not seeing any teams is that you're not a member of any teams, and there are no public teams within your organization.
Please consult your Teams Admin for more information.