Most common Lego piece? I know there are many candidates for a rarest Lego piece, but:

Is any specific brick truly the most common? Which? Which color?

I've wondered for a long time about this.

Make sure to include details, as in proof, and if a line is blurry, defend both points.
If you look at the quantity of parts in all sets, the most common is the 1x2 brick ignoring color. The most common part and color combo is the Techhnic pin with friction in black.



These stats were pulled from Rebrickable's database - they previously had a "Stats" page, but this has since been replaced with their API.