NVMe (Non-Volatile Memory Express) is an interface protocol built especially for Solid State Drives (SSDs) to utilize the high-speed PCIe bus in computers. M.2 is a form factor that is commonly used for NVMe SSDs due to its compact size and direct connection to the PCIe interface, which is ideal for laptops. The 2.5" and 3.5" form factors are more commonly associated with SATA drives, and SD is a form factor used for removable flash memory cards, not for internal storage solutions like NVMe SSDs.