There's a way to search workflows from a Time Machine Backup by name.
It might seem like a lot of work but it's done in minutes.
tl;dr: Replace the "plist" extension in a copied version of the "Alfred.alfredpreferences" Backup with "txt". Then search for whatever you recall from your lost workflows name.
1. Open your Time Machine Volume in Finder
2. Go to the desired Backup date
3. Go to file "Alfred.alfredpreferences"
4. Right click the file, then select "Show package contents"
5. Copy folder "workflows"
6. Paste the copied folder to your prefered destination (e.g. "/Users/USER/Desktop/")
7. Open the copied folder
8. Hit CMD + F to start a search
9. Click the Plus sign
10. Select "Dateisuffix" from the first drop down menue (guess it's something like "Filesuffix" in english)
11. Hit CMD + A to select all results
12. Right click the file, then select "X Objekte umbenennen" (should be something like "Rename X objects")
13. Select "Text auswählen" (should be "Replace text")
14. Type "plist" in the next field
15. Type "txt" in the next field
16. Go to the folder you've pasted in step 6.)
17. Hit CMD + F to start a search
18. Click the Plus sign
19. Select "Inhalt" from the first drop down menue (guess it's "Content" in english)
20. Type whatever you recall from your lost workflows name.
By the way, deanishe, I've recently found your Fuzzy search workflow and it totally changed my use of DEVONthink databases. Thanks a lot!