If we can think of it, it's probably a thing. If it's not a thing, then by thinking about it, it probably became a thing. A thing can be a thing just by being thought of.
Things are weird that way.
Everything is a thing at one time or another. Do things that were ever stop being things? Probably. But then thinking about the thing not being a thing makes it a thing again. So probably not.
I wonder if there was a time when things didn't exist. Was there anyone around to think about things before things existed? Did things come into existence because they thought of them? Are we thinking things into the past by thinking about things that were in the present?
Are we things?