Upgrading an older iMac's PCIe SSD: Third-party solutions that save you beaucoup bucks | Macworld
Amazon.com: LEVEN 1TB Mac Upgrade NVMe SSD PCIe Gen3x4 Compatible with Apple MacBook Air (2013-2017) & Pro (2013-2015), Mac Mini (2013) & Pro (2014), iMac (2013-2019) : Electronics
Apple 1TB (2x512GB) PCIe Flash SSD Kit for 2017 Apple iMac Pro 656-061A EMC 3197 | eBay
APPLE 32GB NVMe PCIe SSD FUSION DRIVE - iMac 21.5 A1418, 27" A1419 Late 2015 | eBay
How to Install a PCIe SSD in a 27-inch iMac with 5K Display
Genuine Apple 4TB (2x2TB) PCIe SSD for: 2017 iMac Pro A1862; 2019 Mac Pro A1991 | eBay
Amazon.com: PCIe NVMe Gen3x4 SSD 1TB 512GB 256GB 128GB 3D TLC NAND Flash Hard Drive SSD Replacement for Macbook Air 2013-2017, Macbook Pro Retina 2013-2015, iMac 2013-2017, Mac Pro 2013, Mac Mini 2014 (1TB) : Electronics
Upgrading a 27-inch iMac 5K to 14 terabytes - Replacing the Fusion Drive with both a SSD and an harddisk
KingSpec 256GB 512GB 1TB M2 PCIe NVME SSD For 2013 2015 Macbook Pro Retina A1502 A1398 Macbook Air A1465 1466 SSD iMac A1419 SSD|Internal Solid State Drives| - AliExpress
Apple iMac 128GB PCIe Internal SSD Hard Drive Storage (Samsung MZ-KPW1280/0A7) | eBay
Amazon.com: Cloudeck NVMe SSD 512GB PCIe Gen3x4 Internal Solid State Drive with 3D NAND for MacBook Air (Mid 2013-2017), MacBook Pro(Retina, Late 2013-Mid 2015), Mac Pro(2013) & Mini (2014), iMac(2013-2017) : Electronics
How to add a fast new SSD to your old Mac or MacBook for only $150 - 9to5Mac
128GB FUSION DRIVE PCIe SSD Apple iMac 21.5" A1418,27" A1419 Late 2013,2014,2015 | eBay
INDMEM NVMe PCIe SSD 256GB 3D TLC NAND Flash Hard Drive Replacement for Mid 2013-2017 MacBook Air, Late 2013 - Mid 2015 MacBook Pro Retina, Late 2013-2017 iMac, 2013 Mac Pro, 2014 Mac Mini
IMac's upgrade PCI-e SSD - Apple Community
2013 MacBook Air NGFF PCIe SSD Review (256GB) - Pre-Configured MBA Doesn't Set The 'PC' Performance Bar | The SSD Review
How to Install a PCIe SSD in a 27-inch iMac (2019)
2013 iMac teardowns reveal SSD slots, soldered-in CPU in the 21.5” model | Ars Technica
iMac 2013 (and later) with NVME SSD? | MacRumors Forums