Working with flows is very messy if you are working on a batch of flows that contribute to one task. A system of being able to tag flows or put them in folders would allow you to work more seamlessly on specific flow groups.
You can now organize your flows into solutions. Solutions are like tags or folders. They are like folders in that they can contain flows, plus they can contain other assets like PowerApps, CDS entities etc.... They are also like tags in that a single flow can be in more than one solution - so your not tied to one strict heirarchy. The new Solutions tab is available for any envirnomnet that has CDS enabled. Read more here: https://flow.microsoft.com/blog/solutions-in-microsoft-flow/