The Common rarity is the most found rarity in the Yu-Gi-Oh! card game. Commons are plain cards without any shiny parts and in regular Booster Packs of 9 cards you'll find 7-8 Commons. You also have the Normal Rare which is exactly the same as a Common except they are harder to find Commons. Normal Rares are only truly found in the OCG Booster Packs.
Related ThreadsI can't find my common dir - last post by @ Jan 10, 2013
Yu-Gi Common Files - last post @ Jul 23, 2007