OWC SSD Upgrade Kits for 21.5-Inch iMac (2013 - 2019)
Apple iMac (27-inch, September 2013) review: New processors and faster Wi-Fi for Apple's slim desktop - CNET
Apple Samsung 128GB PCIe SSD for MacBook Pro, iMac, MacPro Late 2013–2015 | BIZON Custom Workstation Computers, Servers. Best Workstation PCs and GPU servers for AI/ML, deep learning, HPC, video editing, 3D
NVME 512GB SSD For Apple iMac 21.5 A1418 EMC 2638 Late 2013 3 Years Warranty | eBay
Apple iMac 21.5” SSD Upgrade (2013-2015) HDD To Solid State Drive (SATA) | Step By Step - YouTube
iMac 27 2012-2015 Hard Drive Replacement with SSD
The OWC Aura Pro X2 SSD Review: An NVMe Upgrade For Older Macs
An External SSD Gave My iMac a New Lease on Life - TidBITS
iMac 21.5 and 27-inch 2013-2019 PCIe NVME SSD|FlexxMemory|free UK delivery
iMac Hard Drive Upgrade to SSD - Your local Apple Repair Specialists