One particular feature in Microsoft Teams that has been a success in my organization is the use of Cloud Storage to provide a hierarchy in Microsoft Teams. If you are not familiar with what I am talking about, I am referring to the Add cloud storage link you see in the Files tab of a Team. You might have glossed over this link since you may be fully on Office 365, but this particular link has a lot of power.
Clicking that button will take you to a screen asking you which cloud storage provider you want to use. In our case, we want to use SharePoint.
However, you may have different options. That's because they can be configured in the Office 365 Admin center under Settings -> Services & Add-ins -> Microsoft Teams -> Custom cloud storage.
Note, how most of mine are turned off. Google Drive is about to join the off-club as well for us. Having just migrated my organization off of G Suite this cloud storage provider approach has acted as a good transition since Google makes use of the virtual folders concept quite a bit.
Now back when the user chooses SharePoint, it will present you a list of sites that it thinks might be relevant to you. However, you can also paste in a link from any SharePoint site you have. Don't worry about trimming the link or getting it exact either. You can paste the URL of the site root, a document library, whatever. Teams will figure out the site you want.
Paste your URL, select the site, and then click Next. Now pick the document library you want to link in.
Finally click Add Folder.
You will be returned to the Files tab. This part is a bit buggy because while the tab does refresh, it doesn't show you your new link. Just switch off the tab and click back on the Files tab and you will then see your new link.
It will create a link to the child site with a special SharePoint folder icon. It names your folder based off of the site name and document library name. Unfortunately, you don't have any control of that name and you can't rename it.
When you click on the link, it will let you drill down into the document library of that site you linked in. Notice it even maintains the bread crumbs from the Team you came from.
This is a great way to bring links to content from all over your organization into one central location. It's pretty useful I think.
What's the downside?
I think the only other downside is that you can only see these links from the Teams client. If you go into SharePoint directly, you won't see those links in your document libraries. It's still pretty useful though. Give it a try!