These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
One-Scene Wonder: Proto one is the only wave 1 B-daman toy that is not used by the main character. All we see of it in the show is Battle Crow crushing it after defeating its owner, who is never shown. If you blinked, you might have missed it.