I installed Ventoy on mine and dropped a few live ISO files: Clonezilla, Linux Mint, and Windows PE
I'll sometimes use the Windows PE ISO for tools like CrystalDiskInfo. Have Clonezilla to quickly test out random computers without a GUI and Linux Mint when I want a GUI.
The rest of the space comes in handy for quick and dirty file transfers between Linux/Mac/Windows/printers. Especially with my work computer never touching my primary home network, an airgapped retro gaming setup, and most of my other drives formatted for use with Linux.