Lexar's 1TB SD card is the first you can actually buy [theverge.com]
SanDisk showed off a 1TB SD prototype [theverge.com] a couple of years ago, but the final product never made it to market. Lexar's Professional 633x line of SDHC and SDXC UHS-I cards, however, is now listed for sale in capacities from 16GB all the way up to the flagship 1TB. That card claims read speeds of up to 95MB/s and write speeds of 70MB/s, though it's only rated as V30/U3, which guarantees sustained write performance of 30MB/s.
Related: Half a Terabyte in Your Smartphone? Yup. That's Possible Now [soylentnews.org]
SD Association Raises Max Capacity to 128 TB, Speed to 985 MB/s Using PCIe and NVMe [soylentnews.org]