[MENTION=98989]Parker1938[/MENTION] In my completely unprofessional opinion, it looks like a make shaft spacer for the sunroof guide bars. A lot of people have issues with the sunroof rattling, and a lot of people suggest putting a "thing" in to brace these bars. You can see the small guide bars on outside of the sunroof channel when the sunroof is open. I used a small semi-circle bushings to brace mine. Just a thought though.
Another thought. It could be a bushing for a spring under the drivers dash. There was a huge issue with squeaky clutch springs in 1st gen tacomas. These spring bushings would wear out, or fall off, and in turn create a squeak when compressin the pedal. The bushings look very similar to what you found
If you scroll down in this "how to" you will see the very similar looking bushing
Welcome to LIEBLWEB.com's Toyota Tacoma Clutch Petal Bushing Replacement Write-Up!
Edit: 7th picture in the link