I just received an e-mail from Micro Center advertising Samsung 256 gig and Micro Center branded 512 gig SD cards!
Note that, (AFAIK),
neither of these cards are application rated, (see update below), so they won’t be blazingly fast, but they are HUGE - and might be useful if you’re doing dev work, or want to multi-boot. (I’m working on the multi-boot problem using PINN, and I hope to have some PINNified images of the Dexter/MR software soon.)
See the link at the very bottom of this post.
If you use something like Etcher to flash an image to the card, it will attempt to fill the entire card with the image - and as a consequence it will take a LONG TIME to flash. If possible try to find another flashing method that doesn’t try to fill the card, and then use something like GParted (or raspi-config), to expand the last partition.
Looking more carefully, I discovered that the Micro Center branded card IS APPLICATION RATED at A1, so it will have vastly improved R/W speed for random read/writes AND likely supports TRIM! Since the Micro Center card is about $20 more than the half-size, not application rated Samsung card, that’s the one I would go with - unless you’re doing serialized data-logging or video.
Samsung 256 gig