https://www.theregister.co.uk/2018/06/21/samsungs_nf1_doubles_m2_card_capacity_with_wider_gumstick_format/

Samsung's 8TB next-generation small form factor (NGSFF) NF1 flash card is to be standardised by the JEDEC Solid State Technology Association in October.

It measures 11cm x 3.05cm, compared to M.2's 11cm x 2.2cm. In that space Samsung has fitted two rows of four 256Gbit TLC 3D V-NAND chip packages on each side - 16 chip packages in all - providing 8TB capacity. Samsung said this is double M.2 card capacity. In fact, it is quadruple its own 970 M.2 format products.