Itty Bitty Erlenmeyer Flasks!
One of the labs at the university where I work was holding a giveaway to get rid of their old junk. I checked it out, and among the offerings were the tiniest Erlenmeyer flasks:
Each flask holds 5mL of fluid, as you can see in the next picture:
I have no earthly idea what they could be useful for, but there they were.