Do you use Spotify? Then maybe it is the Spotify cache files. Here is a post which seems identical to your issue with similar folder names.
https://community.spotify.com/t5/Desktop-Mac/Spotify-created-a-bunch-of-mostly-empty-folders-on-my-external/td-p/4395857
Did you modify the path for Spotify's files? If not, then maybe the preference file became corrupted and you can delete the Spotify .plist preference file in the "~/Library" folder. Try looking in "~/Library/Preferences" first. After deleting the preference file, log out of the user account and log back in to make sure the app recreates a new default preference file.
If this is not the problem, then you can try running the following command from the Terminal app to see if it catches the app which is creating those items:
sudo fs_usage -w ~/Downloads | grep "$HOME/Downloads" | tee -a ~/Desktop/download_folder_log.txt
You will be prompted for your admin password, but nothing will appear on the screen while typing the password. Press the "Return" key to submit the password and also at the end of the line to execute the command.
This command will monitor the Downloads folder and display the process that modifies items in the Downloads folder. The command will also save a copy of the information shown within the Terminal app to a file on the Desktop called "download_folder_log.txt" so that you can scroll through it if it takes a while before any changes are discovered in the Downloads folder.
Keep the Terminal window open until new items appear in the Downloads folder or until you decide to give up. This utility will only identify standard apps making modifications to the specified folder. If some low level utility is creating those items, then this command may not detect the changes to the Downloads folder. To stop monitoring the Downloads folder press Control + C to terminate this command.