Samsung Galaxy S9 and S9+ Smartphones: Super Slow-Mo Video, Low Light Camera, AR Emoji, IP68 Water & Dust Resistance, Expandable Memory of Up to 400GB with a Micro SD Card, Smartphone Protection
Samsung Galaxy S9 Memory Card 400GB Ultra Micro SD SDXC UHSI Class 10 for S9+ S9 Plus SDSQUAR400GGN6MA with Everything But Stromboli TM Card Reader E-Book Readers - Newegg.com
Best MicroSD cards for the Samsung Galaxy S9 and Galaxy S9+ – Phandroid
Amazon.com: SanDisk 400GB Extreme microSDXC UHS-I Memory Card with Adapter - Up to 160MB/s, C10, U3, V30, 4K, A2, Micro SD - SDSQXA1-400G-GN6MA : Electronics
Amazon.com: SanDisk 400GB SDXC Micro Ultra Memory Card Works with Samsung Galaxy S10, S10+, S10e Phone Class 10 (SDSQUAR-400G-GN6MN) Bundle with (1) Everything But Stromboli 3.0 Card Reader : Electronics
The Best Micro SD Cards for Your Galaxy S9 « Android :: Gadget Hacks
Best MicroSD Cards for the Galaxy S9
Amazon.com: SanDisk Ultra 400GB MicroSD XC Class 10 A1 UHS-1 Mobile Memory Card up to 100MB/s Read Speed (SDSQUAR-400G-GN6MN) with Mini MemoryMarket MicroSD Memory Card Reader : Electronics
SanDisk 400GB SDXC Micro Ultra Memory Card Works with Samsung Galaxy S10, S10+, S10e Phone Class 10 (SDSQUAR-400G-GN6MN) Bundle with (1) Everything But Stromboli 3.0 Card Reader : Electronics - Amazon.com
The newest, fastest "app class" microSD cards are still not very good for apps