SSD products have expanded into a wide array of choices. The typical gaming PC uses the M.2 slot which is provided with x4 PCIe lanes. The M.2 slot typically is 2280 however 22110 is seen with some higher capacity SSD products. SD cards are very popular with digital cameras. See media stamina for a report.
A USB 3.0 front panel box supports flash card readers for all of the common formats. MicroSD cards are used in the digital microscope used for repairing mobile devices.
Some very old EIDE class laptop have been refurbished with an adapter that holds one or two compact flash cards in a tray. This allows an old machine to have maximal capacity of storage. The performance of modern compact flash cards is also substantially faster then the old EIDE hard disks.
Older machines like the Lenovo X220 and X230 use a mSATA based SSD. The machines can also use a conventional SATA type SSD. Kioxia is now a larger SSD manufacturer but the lower cost Kingston brand was selected for the X230 overhaul. Kioxia was established for the growing SSD market.
The old Lenovo T400 has the ability to use compact flash cards in the memory card slot. USB adapters are widely available. Compact flash is still seen with some high end digital cameras.
The AM4 platform support one or more M.2 SSD slots. These are faster than the mSATA and SATA SSD devices. The budget friendly KingDian SSD shows the higher sequential read speeds are far above the SATA maximum.
The KingDian SSD is currently installed in the MSI X470 Gaming Plus. The R5 2400G integrated graphics are being used for a media center platform. The motherboard has a pair of M.2 slots so it can be used for testing secondary SSD devices.
Earlier when the KingDian SSD was installed in the MSI X570-A PRO it was not reported as 4 lanes. A bug in the BIOS caused SSD products to be 1 or 2 lanes. Since then the updated BIOS has fixed the problem and now SSD performance is back to normal.
Server E1.S SSD products are much longer. These are designed for use in vast numbers to assemble a very fast array. These are thin enough to stuff 32 of them into a 1U server box with extraordinary capacity and performance. These servers are very expensive but they are being mentioned so that gaming enthusiasts can see what corporate rigs are using.
The U.2 SSD products are the same size as laptop SATA hard disks and are typically 7mm or 9.5mm with some as thick as 15mm. These can be used by desktop gaming rigs as they fit the hard disk bays of most chassis fine. Micron and Koxia both make U.2 SSD in up to 30TB capacity. Prices are reasonable compared to server grade hard disks.