Apparently Primocache works pretty well. : r/homelab
How to: Set up Intel Smart Response Technology (SSD caching) | Overclock.net
Amazon.com: Kingston Digital 2-Inch 480GB SSDNow mS200 mSATA (6Gbps) Solid State Drive for Notebooks Tablets and Ultrabooks SMS200S3/480G : Electronics
Wdisker SSD 1.8" 64GB IDE SSD Cache Size:256MB flash memory (Made in TAIWAN) | eBay
Amazon.com: M.2 SATA NGFF SSD to USB 3.0 External SSD Case Reader Converter Adapter Enclosure with UASP, NGFF M.2 2280 2260 2242 2230 SSD with Key B/Key B+M(Grey) : Electronics