We don't have a folder feature at this time, but we're constantly working on improvements for you and we do have an alternative for grouping / organizing your saved visuals.
When naming visuals you'd liked grouped together (you can always rename them as well!), you can create names with the same word or phrase for multiple visuals. This way, when this word or phrase is searched at the top of your dashboard, the visuals that contain that word or phrase will show at the same time.
You can also let our developers know you'd like a folder feature here.