Only in groups. I thing it is slightly forgotten and not fully utilised part of TR. I assue not many users is using them so TR team left them as they are but it is only way how you can exchange the workouts and there are some pretty decent packs of workouts (like mentioned SST progression group).
My personal opinion is that TR can benefit a little bit more if the addresses the group of people that love to tinker with their own plans and want to experiment a little bit more with their training. It is quite low hanging fruit from technical perspective, as it is based on manual work of users (so not very sexy or good for PR so I understand from business perspective not very high in TR priorities as it still requires some workforce). It could introduce also some clash with TrainingPeaks, cause the requested features could lead to overlapping functionalities. But we can still dream a little bit (yes, new and better workout creator - I am talking about you).