Amazon.com: SanDisk Ultra 400GB SDXC Micro Class 10 Works with RED Hydrogen One UHS-I Class 10 Bundle with Everything But Stromboli Card Reader : Electronics
SanDisk's 400GB MicroSD card is just $30 on Amazon
SanDisk 400GB microSDXC UHS-I Memory Card for Nintendo Switch SDSQXAO-400G-ANCZN - Best Buy