Yu-Gi-Oh! the Toei anime, also known as Yu-Gi-Oh! Season 0 or Series 0, gets synned with Yu-Gi-Oh! Duel Monsters (Anime & Manga). This is lies. YGO:S0 adapts the first seven volumes of the manga, YGO:DM (which is the one that would be familiar to English-dub-only viewers; S0 was never dubbed into anything but Japanese, I believe, and certainly not English) mostly pretends those volumes don't exist, a character who appeared in one manga chapter ever (Nosaka Miho) is one of the regulars in S0 and doesn't exist in DM, a bunch of the S0 episodes (including multiple recurring characters who also don't exist in DM) aren't based on any manga chapters at all, and heaven help anyone who's trying to timeline as though manga, S0, and DM are the same continuity.

also: someone nominated S0! *squee*