Artwork created during the '00s decade (also known as the noughties/naughties, aughts, or two-thousands) — particularly when the specific year of creation is unknown or the work was created across multiple years.

Posts added to e621 prior to 2010, and are obviously not of the 1990s, 1980s or earlier (due to style, subject matter, or apparent technology used to create the post), and lack a year tag, should fall under this tag.