Ugreen SD Card Reader USB 3.0 USB C OTG Dual Slot for UHS-I Micro SD SD SDXC SDHC Micro SDXC Micro SDHC MMC Compatible for MacBook Dell XPS Samsung Huawei Sony Google
Here are the best microSD cards for the Samsung Galaxy S9 & S9+
USB C to SD Card Reader
Hybrid Sim Slot Adapter to Run 2 Sim and Micro SD Card Compatible for Samsung Galaxy S9 Plus - Pack of 2 : Amazon.in: Electronics
Dual Sim Card / Single Sim Card + Micro Sd Holder Slot Tray For Samsung Galaxy S9 / S9 Plus - Sim Cards Adapters - AliExpress
512GB Micro Samsung EVO Plus SDXC Memory Card (MB-MC512KA) - Everything But Stromboli
Product - avedio links
Samsung Evo Plus 256GB Micro SDXC Card | Flash Trend