There are Seeded or Blind Draw Tournament Brackets.
Blind Draw Tournaments are usually run in events when players are not ranked. For example, tavern or bar tournaments such as Cornhole, Darts, Shuffleboard or Billiards usually have these types of tournaments. Match-ups are based solely on the luck of the draw.
Unlike Blind Draw Tournaments, Seeded Tournaments are set up so that the results of a season or league, and even experience or skill level determines which teams would play against each other in the tournament. The number one ranked team players the lowest ranked seed, the number two ranked team plays the second lowest ranked seed and so on.