400 GB is no longer the biggest microSD card available. As of some time in February 2018, there will be a (very likely expensive!) 512 GB microSD card on the market! : r/gpdwin
SanDisk Ultra 1TB Micro SD Card Works with Nintendo Switch & Nintendo Switch Lite Console (SDSQUA4-1T00-GN6MN) UHS-1 Class 10 Bundle with (1) Everything But Stromboli SD & MicroSD Memory Card Reader
SanDisk 128GB Extreme PLUS UHS-I microSDXC SDSQXBZ-128G-ANCMA
Best microSD cards of 2023: Speed, capacity, cost compared | ZDNET
Sandisk Extreme Micro SD Card 64GB Black | Diveinn
Amazon.com: High Speed Micro SD Card 2TB 100% Real Capacity Micro SD/TF Flash Card Memory Card 1TB Micro SD for Phone/Computer/Camera : Electronics