I have an SSD (along with a USB SATA enclosure to connect it), a spinning disk, and at least one USB thumb drive in my bag that I bring to work every day (along with my laptop).

This is in part because I switch between working from home and working at the office fairly often, have travel time in between, and need to have access to more VMs than I can fit on my laptop's internal SSD comfortably.

I also may have SIM cards rattling around somewhere; when I travel internationally, I buy a local prepaid SIM, and I may have older SIM cards left over from the last time I replaced one.