Found a trio of TBs to log in an old caching notebook. Sorry, I can't remember when I saw them but it was before the pandemic! And probably in Nebraska - most likely Lincoln. Thanks for sending them out into the world!
Update: after looking at the maps for the three TBs on my list, it looks like I probably saw these at the 2015 Coinfest at the Strategic Air Command museum in 2015! :)