SanDisk is one of the most popular brands in consumer memory cards especially those used in prosumer camera gear mainly due to their low cost coupled with high performance and reliability. While it isn't in production yet, SanDisk unveiled a prototype one-terabyte SDXC card at earlier today at Photokina 2016. This card will be marketed for those who are capturing a great deal of data-heavy 4K video footage or simply want a single card to last an shoot from start to finish.
A few years ago, SanDisk unveiled their 512GB SDXC card at this same trade show which was a milestone back yet over the years has become a high-end standard in today's media world. SanDisk currently mass produces these 512GB cards which are selling for just under $350 on retailers like Amazon.
While this card remains in a beta stage right now, I wouldn't be surprised to see it officially hit production and be available for purchase sometime in the next 12 months.