By far the cheapest Micro SD method : r/miniSNESmods
Super EverDrive V2 Cartridge - include SD card (fit in SNES and SFC Console) | eBay
Indie Retro News: SD2SNES - Is this the best SD based device for your SNES? [ BIG Hardware Review ]
SD F-1 Grand Prix - Wikipedia
SD2SNES EverDrive flash cart for the Super Nintendo review - Gamester81 - YouTube
Internal Micro SD Board of SNES MINI Console - J&T Studio
Amazon.com: Over 23,500 Games on 64GB SD Card for Hyperkin Retron 5, Genesis NES SNES Game Gear Master System GBA GBC GB Manuals, Cheats, Artwork, Plug n Play; Retron 5 & adapters