tfm list projects
tfm list projects will list projects by default of the source TFE/TFC instance.

--side flag
Providing the --side destination flag will list projects of the destination TFE/TFC instance.

--json flag
Providing the --json flag will output the project names and IDs in JSON format to make configuring the tfx configuration file more managable.

Note: Projects is a relatively new feature. If the source or destination TFE API endpoint does not support projects, tfm will error out.