What are the best greatest teams of the 21st century? Rank them all with this greatest teams of the 21st century tier list maker. Drag your favorites into S tier and drop the worst into D tier. Share your greatest teams of the 21st century tier list on social media, compare rankings with friends, and see what other Americans think. The ultimate way to rank and debate greatest teams of the 21st century online. Popular categories include sports, nfl, mlb, nba.