The NES and SNES Classic systems support SD cards : r/miniSNESmods
For F-c Adapter For Snes Or Japanese 16bit Console, Play 60pins 8-bit Game Cartridge On 16-bit Console Whit 500 In 1 Game Cart - Accessories - AliExpress
SD2SNES Super Nintendo Everdrive Cartridge With 16GB SD Card 1000+ Games inc. Super Mario Kart | TripleM Gadgets
Amazon.com: Over 23,500 games on 64GB SD card for Hyperkin Retron 5, Genesis/MD NES SNES Game Gear Master System GBA GBC GB Famicom Super Famicom Satellaview SG-1000 SC-3000, MANUALS, CHEATS, ARTWORK, Plug
Retrogate Store: SD2SNES - Flash Cart for Super Nintendo with SD slot and USB - Skooter Blog
Super Nintendo Original Console Bundle with SD2SNES - Stone Age Gamer
Amazon.com: Loaded MicroSD Card for Super EverDrive X5 or X6 - Complete SNES collection, Hacks, Homebrew. : Video Games
By far the cheapest Micro SD method : r/miniSNESmods
Super Nintendo SNES Microsd Card Adapter for FX Pak PRO - Etsy
Amazon.com: Brook Wingman SNES Converter - Retro Gaming Controllers Converter on NES, SNES, New FC, and SFC consoles. : Video Games
Amazon.com: SD Card Reader, uni USB 3.0 to SD/Micro SD Card Adapter, Aluminum High Speed USB to External Memory Card Readers for SD, SDXC, SDHC, MMC, RS-MMC, Micro SDXC, MicroSD, Micro SDHC,