These are game cases specifically designed for SNES and SFC (Super Famicom) game carts (Atari Jaguar carts fit well too). If quality matters to you
BitBox Game Case for Super NES / Super Famicom
Nintendo SNES Game Cartridge Protective Display Case Super
Earthworm Jim 2 [Pre-Owned] (SNES)
Super Nintendo Entertainment System Console [Pre-Owned]
Pieces - Vertical Style - Custom Game Cases for Retro Games by Gaming Relics
3 in 1 AC Adapter - SNES / NES / Genesis 1 - Repair Parts - Nintendo (NES) - Nintendo