Perfect for the Nikon D810.
Memory cards have deep discounts right now.
The one card that has performed flawlessly for me since day one is the Toshiba Exceria Pro 64GB. It is the only card I have used that has never had a glitch. I also use SanDisk and Lexar, but the Toshiba has never disappointed me unlike those two brands.
I like the 64GB (or larger) sized because out in the field it means I can generally leave files on the card as backups even after downloading*.
* Unless it’s Pentax which has a nasty “card is not formatted bug” even on the 645Z (the K3 first made this stupid bug plain)—if anything disturbs the format, such as merely renaming a folder, you’re hosed and have to reformat or hike back to the car for another card.