Can you order from eBay? See https://www.ebay.com/i/133526274111.
Also see hit on amazon.com: https://www.amazon.com/Intel-NUC6i5SYK-NUC6i3SYH-NUC5i5RYK-NUC6i5SYH/dp/B07T7DGRH1
Also get hit on aliexpress.com: https://www.aliexpress.com/item/33040488385.html.
If you can order from China: https://www.cdrtd.com/products/nuc-fan-for-intel-nuc6i5syk-nuc6i3syh-nuc5i5ryk-nuc6i5syh.html
Hope this helps,
Due to this product being discontinued, Intel Customer Service no longer supports inquiries for it, I am glad to see that fellow community members have the knowledge and they jumped in and helped. You may also find the Discontinued Products website helpful to address your request.
Please keep in mind that this thread will no longer be monitored by Intel. Thank you for your understanding.
Intel Customer Support Technician