I don't really carry one anymore, but the one I have at my desk has Ventoy and LMDE on it for when I need to mess with something requiring my system to be down or modify my OS partition. I don't really do much on other PCs except when I have to help my wife with something.
When I was working at my last job I carried 2-3 with a ton of database backups and proprietary software and firmware files for clients' automation systems. Kinda don't miss it at all, but it sure made me feel important, lol.