I had a question on a Filter/Fingerguard for this Fan W2E142-BB05-01 Digi-Key part number 381-1063-ND.
Here are some options that will work.
CR183-ND
CR185-ND
CR189-ND
CR186-ND
These may be a little harder to find. You have to search off of the Diameter of the fan.
These will match up even though it is from a different manufacturer.
If you just search by the original fan size they will not show up.
In this case 150mm would be what you want to choose along with Filter Guard Assembly.
This can aslo work for many other fans of similar dimensions.